Bas Relief: A Great Technique, but is it Ethical? – Mark Pedlar

Bas Relief-1This image as shown was submitted to the Newcastle International Photography Salon in the late 1970s. It was entered in the Pictorial Slide Section. That’s Pictorial (Open) not Experimental, Avant Garde, or Manipulated.  It was accepted for exhibition. That means that the judges not only saw it as “in category” but also in the top third of entries for artistic merit. Patently, it did not come out of my camera like this. It had been modified.

And, let’s get it straight from the start: nobody is suggesting that the images in this article are fine art. They are simply examples available to demonstrate a couple of points.

The original slide was shot from a window of the Zebra Motel in Elizabeth St in Sydney in November 1975 just after a shower had left reflective puddles on the bitumen. This slide was then contact printed onto lith film to give a black and clear negative with no intermediate tones. These two images were sandwiched together in a glass slide, slightly out of register, for projection.


Bas Relief-2 and 3

Bas Reliefs can be made in Photoshop by pushing the appropriate button but the results are not at all like this. You can combine colour and lith images but it is not as straightforward. Using slides all white areas are in fact transparent. With Photoshop files they are by default white. What is more, the pastel areas in your original allow no light through either.

However, working with lith derivations still offers some of the options that were available with slides. The Australian Academy of Science’s Shine Dome also attracted me in 1975. The light was hardly inspiring on the day but again using a lith for Bas Relief made it more interesting.


Poster-1 and 2

Now, if you make a lith negative, you can also make a lith positive of the original.  You can use both liths (positive and negative) to create a posterised image. For those of you who can remember that far back, in the 70s libraries kept miniature copies of newspapers on microfiche. Car spare parts lists were often the same. The microfische was a monochrome image available of the original document.  The images were often reduced in size and were viewed through a microfische viewer which magnified the transparent film.  The film used was diazochrome and was available in several colours.

In the case of my poster image I used diazochrome film.  It was contact printed with the lith image by taking it out in the garden and exposing it to UV light. The resulting image was then developed in a plastic bag with ammonia fumes. The resulting diazo prints looked very much like those below and were used with a third derivative in green to create a posterised effect.

Poster-3 and 4

The two images above are positive and negative liths of the original created using Photoshop’s Filter/Stamp option.  One was recoloured red and the other blue. Now use the magic wand on non-contiguous and the eraser to remove the white areas of each image. Then import both onto a new image with a green background. Hey presto a posterised Shine Dome.


Finally, Bas Reliefs and posterisation were employed as regular manipulation of images 40 years ago. Nobody got up tight about the concept until Photoshop arrived and some folks believed it gave lazy Photographers a cheap way of creating new images.

Nonsense! Photographers have been manipulating the final image after the creation of their original/negative/slide for decades. Ansell Adams was altering contrast and applying localised exposure corrections to the final print under the enlarger. Let’s all get real and embrace all the techniques available to produce better art. Nobody queries how Leonardo Da Vinci achieved the Mona Lisa. Nobody criticises the brushes or palette knives he chose. It’s the result that counts.


  • Bas Relief – is a type of sculpture that has less depth to the faces and figures than they actually have. This technique retains the natural contours of the figures, and allows the work to be viewed from many angles without distortion of the figures themselves.  Below is an example of an Egyptian column with Bas Relief.  The photographic technique that Mark describes simulates the appearance of a Bas Relief by providing dark shadows around objects as if they were carved into stone.

Duck - Owl over eye

  • Contact Print – a photographic print made by placing a negative directly on to photographic paper and illuminating it.   The resultant print is exactly the same size as the negative.  (… as opposed to printing by projecting an image onto the photographic paper with an enlarger, so as to increase the size of the image.)
  • Lith Film – Used in the lithographic printing processes, usually in large sheet sizes because of this more specialized use, but was occasionally seen in 35mm and roll film sizes. This film had high contrast and high sensitivity and was well suited to printing.  The original “blind film” was very sensitive to blue light, but insensitive for green and red tones.  Adding Cyan pigment to the film made it more sensitive to red tones.  This was called “Orthochromatic” film.  It did not produce natural tones and was not suitable for standard photography. (Panchromatic film gave the most natural monochrome rendering for traditional photography)
  • Diazotype –  An image made by the bleaching action of ultraviolet radiation on diazonium salts.  These salts contain a double nitrogen bond.  The “diazochrome film” is produced by coating paper or other medium with a solution of a diazo compound.  Upon exposure to UV light the compound decomposes.  The compound in the unexposed parts is then converted to a coloured azo dye by developing with an alkaline solution or gaseous ammonia.   This produces a positive image.  Many Diazotypes are blue, but other colours are possible.
  • Microfiche – a sheet of film that has very small photographs of the pages of a newspaper, magazine, etc., which are viewed by using a special machine.

Mark Pedlar

Editorial Note

You can easily create the “Bas layer” in photoshop by using the “threshold command”  This dialog gives you a slider whereby you can choose the exact tone when the image would switch from white to black.                                                                  


Post Script

One Feature that was always attractive to me when doing Bas relief work, was a fine white highlight on one side of the blackened areas.  I was having difficulty creating this effect in photoshop.  Then I chanced upon the concept of creating a negative duplicate of the bas layer and slightly offsetiing this in relationship to the black layer.  You can see my three layers in the sidebar of the photoshop window below.  With 3 seperate layers I have created the effect that I want.  See bottom image.




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