Album cover
Album cover
Album cover
Emily Lee
Pinhole, Photograms, Chemigrams
Chemigrams
Pierre Cordier
Untitled chemigram by Pierre Cordier - n.d.
Pierre Cordier is described as the father of chemigrams. He invented the process in 1956, combining the physics of painting (varnish, wax, and oil) with the physics of photography (light sensitive emulsion, developer, and fixer). This process creates images without the use of a camera or a darkroom.
A chemigram is created with the use of developer, stop, fixer and of course the light sensitive paper. Using an object of your choice (a more absorbent object will work better - such as a leaf or a flower) you can create a black and white recreation with light sensitive paper and some simple chemicals.
-
Coat your object in the developer
-
Place your coated object onto the light sensitive paper for roughly 30 seconds (depending on the opacity of your object)
-
Remove your object and place your light sensitive paper in the stop
-
Agitate (shake) the tray of stop to ensure that the entirety of the image is evenly covered
-
Place your image in the wash (a tray of water that is constantly filling) to clear all of the chemicals on the surface
This will create a positive image, however you can repeat this process using the stop first and then the developer to create a negative image. This effect is created due to the facet that where the developer touches the paper it will react and turn black, and where the stop touches the paper it creates a barrier stopping the developer from reaching the paper (hence the name 'stop').
Response
For my first attempt, I decided to apply the stop to the ferns I had collected and apply them to the paper in order to create a negative image (relating back to the previous negative images created in the cyanotype process). I then placed the image into the developer to darken the areas of the image that the stop had not touched. However, I unfortunately pressed down on the ferns with my gloved hand that had excess stop on it and so there are no clear, defined lines in the resulting image. I hope to retry the process in this particular orientation as I feel that the use of negative space creates a darker overall image which I could use to apply meaning to my future photographs.
In my second attempt, I first applied the developer. I coated my compilation of vines and berries in developer which darkened the areas of the paper that it touched. I then proceeded to place the chemigram in the stop, to preserve the image. This attempt is better than my first, with some details present, however it is still not an entirely competent chemigram as the is no real image. Learning from my mistake last time, I did not press down the objects with my hands to avoid completely coating the paper with the developer on my gloves. However, because I did not press them down, the objects did not sit correctly on the paper and thus were not completely clear. I had also added some drops of developer around the image to create the impression that the leaves were falling apart. Unfortunately, due to the lack of clarity of the objects, the added drops merely made the image look messy.
My third and final attempt was the best. In this chemigram, I again applied the developer to the object first so that the area where the object sat became darkened, creating a positive image. Here, I managed to correctly guess the length of time required for the object to be on the paper in order to gain a defined image (roughly 45 seconds). Again, I added the drops of developer around the image to make it appear as if the leaf is falling apart, making the image more dynamic as a whole. This, I feel makes the image more impressive as the process of creating chemigrams is absolutely a process to capture static objects.
The idea of using the surrounding developer droplets was inspired by Leann Shamash's 'Leaf: A Portrait' series in which she captures the fine structural details of different leaves of varying states of decay.
"Untitled" from "Leaf: A portrait" by Leann Shamash - n.d.
Photograms
‘Still life with wine glass’ by Abelardo Morell - 2006
First invented possibly as early as the 1790’s by Thomas Wedgewood, a photogram is the creation of a print via the direct contact of objects onto a piece of light sensitive photo paper. Wedgewood is the first documented user of ‘silver pictures’ - photographs created by the darkening of silver nitrate when exposed to light. It is believed that Wedgewood experimented with the use of paper and white leather with silver nitrate solution (and discovered that white leather was more sensitive) and had intended to utilise a camera obscure in his photograph process, but was unable to due to the limited sensitivity of the chemicals he used. The main issue with Wedgewood’s images were that he couldn’t find a way to 'fix’ them after the desired exposure had been reached and hence all of the images would continue exposing and eventually became entirely black. It is as a result of this that it is unknown if any images from this period have survived.
In order to create a photogram, objects are composed to the artists liking and then a light is shone over the paper at a specific brightness for a specific time in order to expose the paper. Once this process has been completed, the paper is placed into a bath of solution which is agitated for roughly 30” in order to coat the entire image with the chemical and hence develop each part evenly. Once an appropriate stage of developing has been achieved, the artist removes the image from the first tray of solution - shaking it to remove as much of the chemical as possible and make the image crisper - and carefully transfers it to the next. This next tray contains a solution
known as stop. This chemical does exactly what it claims to, and ‘stops’ the further development of any of the paper. The image sits in this solution again for around 30”, and is agitated once more in order to ensure that all areas of the image are covered with the stop and the development of the entire image is halted. The image is then carefully removed and shaken and placed into a third tray which contains a chemical known as ‘fixer’ for roughly 5 minutes. This solution sets the image and (along with the stop) prevents any further developing. Finally, the image is left to sit in a wash (normally water) for around 15 minutes in order to remove any remaining traces of chemicals. This is the basic process, however the timings are extremely subjective and rely heavily on the artists intentions for the image and their creative motives.
This process can produce either negative or positive images depending on whether a negative or positive object was laid on the paper. The use of physical objects such as leaves or feathers will produce a negative print as where they lie on the paper blocks the light from it, preventing in from exposing. This means that when the paper is placed in the developed, only the areas around the object will turn dark. Meanwhile if a negative is used (such as a negative image printed onto acetate - as used earlier for cyanotypes), then the light will shine through, producing a positive image. Additionally, dependant on the transparency of the object used, an incredible variation in tonality can be produced.
First attempts
This print is a test strip. To produce this, I cut a small slice of photo paper and set it up under the enlarger. I then covered the slice of paper and revealed a small section to the light each second in order to test exposure times and how they turned out on the paper. I exposed the paper in sections, ranging from a 1 second shutter speed to 8 seconds.
After producing this test strip, I developed it and made a judgement of the exposure time that best suited the paper. My personal preference was for around 5/6 seconds.
From my test strip, I decided to use an exposure time of 5 seconds to produce this image. I used the enlarger’s light at the largest aperture in order to allow the most light to hit the paper. My initial composition was a slightly eclectic mix of different opacities - feathers, leaves, and a Christmas decoration - which allowed me to explore the effect of different transparencies on the shapes and tones of the print produced. I discovered that the gaps between each individual part of the feathers allowed the light through and consequently created a beautiful tonality across them. The leaf and the Christmas decoration however were much more opaque, preventing any transmission of light through them and thus producing large, blocky areas of white where the paper is underexposed. This effect may seem undesirable, however it may be useful later on to create a greater contrast.
For this image, I continued my experiments with feathers and their tonality. I also added a magazine image with text on the other side to see if the light shining on it would allow the text to shine through and be overlayed onto the image. Unfortunately, my exposure time of 5 seconds was far too short for this effect to occur.
I continued with the magazine image, this time using an exposure time of 10 seconds to try and get the text to appear ion the print. I also dampened the paper and rubbed away some areas in order to make parts more translucent and produce a larger range of tone within the print. These areas are much more pronounced in the image, with the lines of text beginning to show through.
This image (and others) experienced a white border of unexposed paper. This is due to the clip under the enlarger slightly covering the paper which I did not notice due to my working in darkness.
Again I attempted to expose the magazine. I repeated my process of dampening the image and rubbing areas away to produce an increased transparency. I also upped the exposure time to 20 seconds to try and show the text. This exposure time worked much better, allowing a much greater variation in tone across the magazine. However, the longer exposure meant that some of the details of the feather were clipped out in the shadows. This shows that like a camera, film has only a limited dynamic range and is unable to expose for both the highlights and the shadows in a single image without any clipping.
Man Ray - Rayographs
Man Ray is the adopted name of Emmanuel Radnitzky, changed due to the prevalent discrimination and anti semitism in the late 19th century and early 20th century (and through to the present day). Born to a Jewish, Russian, immigrant family in Philadelphia, Man Ray’s family moved quickly to Williamsburg in Brooklyn, New York. Ray spent most of his childhood here with his his tailor father and seamstress mother whose influence is evident in many of his works.
First and foremost a painter, Man Ray was initially inspired by cubism and expressionism, but after meeting Marcel Duchamp, he turned his attention more to dadaism - an art form dedicated to questioning the meaning of art itself and the way in which it is perceived. It was movements such as these that inspired him to shift to the motion that the concept of a piece is worth more that the piece itself. Spending most of his career in Paris, Ray became an influential member of the international Dada and Surrealist circles of artists and writers (which included artists such as Dalí, Magritte, and Picasso).
Ray was also well known for his interest in photography, in particular his distinctive camera-less images which he named ‘rayographs’ which he invented by complete accident.
“One sheet of photo paper got into the developing tray—a sheet unexposed that had been mixed with those already exposed under the negatives—I made my several exposures first, developing them together later—and as I waited in vain a couple of minutes for an image to appear, regretting the waste of paper, I mechanically placed a small glass funnel, the graduate and the thermometer in the tray on the wetted paper. I turned on the light; before my eyes an image began to form, not quite a simple silhouette of the objects as in a straight photography, but distorted and refracted by the glass more or less in contact with the paper and standing out against a black background, the part directly exposed to the light.”
Rayograph spiral by Man Ray - 1923
In Ray’s 1922 spiral series in particular (an image of which is shown above), there is a great deal of evidence for his change from dadaism to surrealism, with the smooth curves and wispy cloud-like structure in the background of his images resembling the dream-like landscapes of the works of surrealist artists such as Dalí and De Chirico.
I am inspired by the abstract compositions of Ray’s work, and the movements that he was involved in and hence I intend to produce some of my own.
Second attempts
This image is a second test strip that I produced for my second attempt at darkroom photograms. After my last attempts being slightly underexposed, I decided to try a slightly longer exposure time.
This image was an attempt at multiplicity in the form of a photogram. I created this image via four separate exposures of 2 seconds each. I placed the feather down in one spot, turned on the light for 2 seconds and the turned it off and repositioned the feather. I repeated this process until I had four representations of the same feather in one photogram.
The feathers are not as clear as I would like however, due to the fact that after having the feather prevent light form hitting it for two seconds, each piece of paper under the feather was still exposed for a further 6 seconds with no coverage, therefore making the feathers more grey, and detracting from the contrast of the image.
Here I decided to experiment with motion. I positioned the feather and exposed it for two seconds before proceeding to drag it across the paper for a further 6 seconds. This created a blurred leading line emanating from the feather, juxtaposing its sharply fixed position. Additionally, the placement of the feather in the top left third with the trail behind it gives the impression of motion and almost makes it appear like a shooting star.
However, I again experienced the slight greying of the fixed feather due to the additional exposure of the paper without the feather blocking it.
In order to rectify my mistake from the previous image, I used a second feather to drag across the paper whilst the original remained in a fixed position, hence appearing more clearly in the final image. Despite this, I don’t feel that this image is quite as compositionally;y strong as the previous photogram largely due to the positioning of the feather within the frame. In the prior image, it was positioned on the top left cross of the third lines, thus drawing the viewer’s eye and making the image more visually appealing. In this image however, the feather is too far to the corner, hence making the image seem slightly ‘off’ and more amateurish.
For this image, I made use of a light bulb in order to experiment with the effects of transparent objects on the image produced. I exposed the paper to the light of the enlarger for approximately 7”. This allowed for the majority of the light bulb’s glass to turn black when developed, however the traces of where the glass was blown in its creation are evident through the visibility of faint white lines circling it. These lines are where the glass is slightly more opaque due to the uneven nature of its surface.
I noticed on my previous image that there was a fingerprint visible on the bottom of the paper from where I had accidentally pressed my finger onto the paper. I decided to experiment with this and produce an image attempting to (this time purposefully) incorporate fingerprints. I pressed my fingers onto the paper for around 2” in order to produce an outline of them. I then proceeded to remove my hand and expose the entire paper for a further 2” to allow the general fingerprint produced to be defined. However, the image did not turn out as I had envisioned, with the fingerprints barely visible due to the underexposure of the paper.
I reattempted my fingerprint idea, this time exposing the paper for longer (7 seconds). I repeated the same method, but this time applied a little water to my fingers to observe the results. This image turned out much better than the first, with some fingerprints clearly visible, however I believe that this was solely due to the longer exposure of the paper (3” on, 4” off) and the water actually had a more detrimental effect, blotting out the pattern of the fingerprints.
Moving on to a different idea (inspired by Kathleen Velo), I decided to experiment with the use of water in my image to see the contrast between fluid and liquid components. I filled a shallow jar with water and set in on the paper, using an exposure time of 9”. Despite my attempts to maintain the bubbles produced from pouring the water into the jar, they simply disappeared too quickly so be seen in the image, and thus the photogram shows only the outline of the jar (due to the transparency of the water).
Compositionally, I placed the jar slightly to the side in order to place it on a third line and make the image overall more attractive to the viewer.
I reattempted my water shot here, this time using my finger to produce splashes inside the jar. Due to the shallowness of the jar, some water escaped onto the outside paper. This produced an extremely messy background, however I quite like this effect as it gives the impression that the water cannot be contained and borders on the romanticist idealism of the natural world being omnipotent.
Unfortunately, the image is rather grey, with details lacking in the shadows. This is as a result of a slight underexposure.
Improving on my previous image, I not only increased the exposure (from 7” to 10”), but also added a light bulb, a feather, and fingerprints to my composition. This produced additional juxtaposition between the natural world and human civilisation. The messy background this time inspires the feeling of a struggle between the two forces, but the domination of the image by the man-made jar and lightbulb make it seem as if nature is losing, thus moving away from romanticism.
Pinhole
‘Turning point’ from "NOT MYSELF: A Path to Transcending Trauma" by Mary Riggs Ramain - 2012
The art of pinhole photography is a process by which images are taken via the use of some sort of container that is darkened inside with a tiny pinprick in the front, allowing light to enter. At the back of the container sits a sheet of light sensitive paper that when the pinhole is uncovered, is exposed to the light of the scene before it. This produces an inverted image due to the fact that light travels in straight lines and consequently the top of the image will appear at the bottom of the paper and vice versa. The image is also a negative as the paper turns black in the highlights as a reaction to the light touching it. This negative can be turned into a positive either by scanning it into a computer and inverting the colours (a more modern technique) or by placing the image over a fresh sheet of paper and using an enlarger to shine light over it. The light will more easily pass through the whites of the original print (the shadows of the actual scene) making them dark and the reverse for the darker areas of the original, hence producing a positive image.
Pinholes are an ancient concept, thought to have been used thousands of years ago by normandic tribes of North Africa who lived in animal skin tents and used tiny holes to project an image of the scene outside. In the 5th century B.C. the Chinese philosopher Mo Ti recorded the formation of an inverted image with a pinhole, and later on in the 4th century, Aristotle also wrote about the images produced by pinholes. In the 14th century, Renaissance artists turned to optics to help amend perspectives in their paintings and produced a device known as the camera obscura. This was a box working on the pinhole basis. The image reflected onto the back of the box was used as a reference for artists to ensure that their perspectives were correct. Centuries later, Nicophore Niepce produced the first known images - his ‘heliographs’ - in 1822 via the use of silver nitrates on paper to make it light sensitive. However, the issue remained as to how to go about ‘fixing’ the images. After astronomer and scientist Sir John Herschel discovered a way to preserve the images, the development of photography truly began. Sir David Brewster - an English scientist - is credited as being one of the pioneers of pinhole photography, coining the phrase is his 1850’s book “The Stereoscope”.
This technique has been modernised and it is now possible to purchase some light sensitive paper and place it inside almost any item. Using a small hole in the object as the aperture, the paper can be exposed to the light for a certain length of time and then covered in order to preserve the image. Once this paper is developed, the scene viewed by the the ‘camera’ will be visible. Interestingly, pinhole cameras have an infinite depth of field - although the most distant objects will always be slightly blurred due to the volume of particles in the atmosphere between them and the camera.
Roma Anderson - Ali
"Untitled" from "Ali" by Roma Anderson - n.d.
This image is one of a series of pinhole photographs named ‘Ali’. This is my favourite of the series by Roma Anderson, which depicts a face, but in a somewhat abstract form with apparent multi exposures of the features, slightly obscuring the face as a whole. The background remains unchanged so we can assume that it was the model - rather than the camera - that changed position during the exposure time. This slight multi exposure produced an image relating somewhat to the work of Francesca Woodman with monochrome images of blurred faces. However in this case, the image is a negative of the scene as a result of the use of light sensitive paper turning black in the areas the the light touches. This inversion of highlights and shadows creates an additional layer of confusion, on top of the already unsettling atmosphere produced by the multi exposure of the face.
The overlapping of the multi exposures has prevented light hitting some sections of the paper entirely, leading them a clean, bright white. Meanwhile, the movement of the face allowed for some light to enter the camera and hit the paper where the face had been previously covering it.
This turned the paper darker in these areas and hence produced a graduation of tone across the face and produced areas of greater contrast (i.e. an area of deeper shadow to greater juxtapose the highlights). This creates almost a colour counterchange with a small area of shadow sitting within a larger area of highlight and more shadow bordering down the left side of the image.
First attempts
Here are evidenced my attempts at creating pinhole images. I attempted to use a variety of different subject matters in order to experiment with how they appear on film. I also made use of two different light sources (natural ambient, and ceiling lamps) in order to see what different effects they would have on the exposure of the image.
1
For this, my initial pinhole image, I decided to take inspiration from Roma Anderson and Francesca Woodman’s work via the use of a monochrome representation of the human face. In order to expose the face, I used a series of 20 strobe flashes which lit the face, but the distance of the face from the background allowed a large light fall off, creating a high contrast and isolating the model. The flashes did also unfortunately illuminate the desk between the camera and the model, thus making the model less contrasted with the background.
Additionally, the camera was slightly askew, leading to the model’s face being positioned slightly to the left of the image. This does allow his face to sit on a cross of thirds, however as a portrait, I would’ve preferred to have the face as large as possible in the centre of the image in order to make the image more directly address the viewer and to produce more of a confrontation.
The brightness of the ceiling lights ensured that they were also a part of the image. I quite like this effect however as they juxtapose the darkness of the rest of the image.
Negative
Positive
11
For this image, I decided to experiment with what would happen if I directly exposed a ceiling light to the paper as my main subject. I propped the camera up on a stool placed on top of a table in order to get it as close to the light as possible (learning from my prior image where the subject was far too small in the frame). However, the resulting image showed still that my camera was both too far away and not directly facing the subject.
Despite this, I feel that the details of the light came out reasonably well in the print. The exposure time was 2 minutes, which I feel was about right for this subject. Any longer would have resulted in a complete over exposure of the light source, whilst any shorter would have produced an image so underexposed that it would be incredibly difficult to make out.
111
Negative
Positive
Here, I expanded my trials to include natural light in my pinhole images. I returned back to the corridor I used for my favourite HDR image, drawn in by its beautiful leading lines and large glass panels. I exposed my image for 2:30 minutes, as the day was cloudy so there was fairly limited sunlight. Unfortunately, I feel that this exposure was not quite long enough, with the resulting print being hugely underexposed.
The immense drop in light levels from outside to inside created a huge contrast of highlights and shadows. This is what caused the image to be underexposed overall. What we can see of the outside world appears to be correctly exposed, with a nice graduation of tone, so we are able to deduce that the exposure time was in fact correct for this image. Despite much of the shadows being clipped out, a longer exposure would have resulted in the entirety of the outside being clipped out. This image (similarly to my previous image with immense light and dark areas) serves to show that pinholes may be able to include a massive amount of detail in their images due to the practically infinite depth of field, however they are very much unable to cope with different levels of light - i.e. the have a low dynamic range.
Negative
Positive
1v
This image was my second attempt at producing and image of the glass corridor. Here I decided to adjust my angle slightly from the previous shot, moving further forwards in order to remove the shadowed area at the front - as seen in the last image. I also increased the exposure time slightly due to a slight weather change which decreased the light level.
However, I feel that the image would have been best if I’d kept the exposure time the same as before. Furthermore I had rested the camera against my legs in order to try and stabilise it for the shot, however I shuffled it slightly, which resulted in a multi exposure (creating an unintentional link back to Roma Anderson’s work). During my exposure, there were a couple of people walking down the corridor. I was interested to see if I would be able to capture their motion in my image. Unfortunately my exposure was far too long to be able to fix split second positions and hence the people that walked through are invisible in my print. I may reattempt the motion idea, but next time using a much larger group of people that move at a much slower rate so that they actually show up on the resulting image.
Negative
Positive
Justin Quinnell - 6 month solargraph
The Clifton Cathedral in Bristol, UK.
A 6-month duration exposure by Justin Quinnell - June 19th 2009 till December 20th 2009
Justin Quinnell is widely regarded as the father of a modern technique known as ‘solargraphs’. These images are produced via a pinhole camera over a period of six months. The camera is set up in a fixed position, (tightly secured to prevent any kind of multiple exposure in the image) and the light trails produced by the sun are effectively ‘burned’ into the paper.
For this image, Quinnell used a beer can as his pinhole camera, lashing it to a post for the six month period. This exposure time is only able to produce such images due to the type of paper used within the can. Using a lustre effect paper prevents the reflection of light onto different parts of the paper that may ruin the image. This extreme length of time allows for the visibility of the different heights of the sun’s journey through the sky in various parts of the year. It is best to set up a solargraph to include a solstice within its exposure time in order to show a larger diversity of sun trail heights.
Quinnell’s use of an aluminium can two take his images produces a slight warp of the image due to the curvature of the paper within its container. Though this effect does actually suit the type of image produced, visually echoing the sun’s motion.
Box Brownies
Introduced in 1900, Frank A. Brownell’s box brownie camera brought casual photography to the public. Its unique low price combined with the low price of Kodak’s roll film and processing resulted in the box brownie camera surpass its marketing targets, with 150,000 cameras sold within the first year of production.
The camera itself was a relatively simple construction, although fairly revolutionary in its time. At the front of the box sat an aperture (allowing a similar mechanism to a camera obscure). This aperture contained a slightly curved lens, allowing the light to be focussed onto the back of the box, and hence producing a sharp image. The internal mirror system allowed for a representation of the image to be viewed before the photograph was taken. This “viewfinder” was one of the most important features of the camera, allowing the consumer to actively choose compositional features in their images and hence help to pave the way for modern, creative photographers.
As the brownie was meant to be an accessible camera for the public to take ‘snapshots’ with, most of these cameras came with a set shutter speed. However, there was also an option to use a lever on the side of the camera to manually open and close the shutter in order to adjust the exposure for different light conditions.
Kodak Brownie Flash III by 'NotFromUtrecht' - 2011
First attempt
For my first attempt, I intended to take a portrait image. However, I had mistakenly left the shutter open in the period between leaving the darkroom and taking the image. So when I had believed that I was taking an image, I was intact closing the shutter for a short period of time, resulting and a completely overexposed mess that turned my paper entirely black.
I hope to re-attempt this process, ensuring that I am entirely comfortable with when the camera’s shutter is open and closed.
Second attempt
Raw
For my second attempt, I took the camera under the red light in the darkroom and checked which lever direction corresponded to the opening of the shutter and hence was able to actually produce an image.
Due to the use of light sensitive photographic paper (the same as used for pinhole photography) the images produced were negative versions. I attempted both a portrait and group image. It would have perhaps been more of a sensible option to use the landscape orientation of the camera for the group shot in order to make the group appear bigger in the frame and hence minimise background distractions.
Via the use of Photoshop, I inverted the negative images to produce the positive versions. This process could have been completed manually, by placing the negative over a black piece of light sensitive paper and shining a light through in for an extended period of time, however the digital inversion is far quicker and easier.
My portrait image appears to be mostly well exposed, however there is some slight highlight clipping over the model’s face, suggesting that my shutter speed of 3” was slightly too long. Additionally, the model is not in focus in this image, whilst the background is. This could be due to the model being too close to the camera - there is a minimum focal length for all cameras, any part of the scene closer to the camera than this minimum distance will be out of focus. Unfortunately this effect produces distraction from the subject, not isolation them as I would have preferred. I specifically positioned the model to have their body and head facing off to the right (left in the image due to the inversion of the image in the same style as the camera obscura) at a 45 degree angle as it gives the model more depth than having their body at a parallel to the camera. It also produces a more serene, thoughtful atmosphere.
For my group shot, I also used a shutter speed of 3”. From the immense highlight clipping that almost completely obscures the faces of the models I can tell that this speed was far too long. However, the composition is reasonably good, with the models sat at varying heights, producing depth in the image. Additionally, the odd number of models makes the image more natural and relaxed. The background was reasonably clean, but I feel that a busier background would have been more apt here in order too provide context to the image.
Inverted
Processed
After inverting my images, I took the into Lightroom in order to make them more visually pleasing. For both images, I increased the contrast to make them look less washed out. I also dropped the highlights in order to decrease the clipping as much as possible, but increased the exposure to prevent the image from becoming too dark overall.
Furthermore, via the use of clarity and sharpening I was able to somewhat save the portrait image, bringing more focus to the model. The addition of vignetting also helped to isolate the subject from the background.