CCC Forum

It is very good to be connected again directly again to CCC. It was the late Dudley Styles, the owner of the camera shop in Dorking, who introduced me to the club in ???? either the late 1950s or early sixties, it is too long ago to remember. The meeting place was the studio of a sculptor called Spackman. It was very lively, we had a reputation for interrupting judges! I was an active member when I got my ARPS and my first Fellowship, and I was responsible for persuading the club to join Photeurop, the exhibition of modern European photography organised by clubs in Brussels, Lausanne and Versailles. The first time Croydon did the heavy work, in 1967 I think, we covered the walls in the main room at the Fairfield Halls, and managed to get Lord Goodman, Chairman of the Arts Council, to open it. We even succeeded in getting a gold medal from the Foreign Secretary as the principal British prize, a unique honour. And of course I was a member of Photo Group 7 which eventually created Modfot One, the unique exhibition of modern British photography which opened in london in May 1967 and then toured 12 art galleries in Britain and, under the auspices of the British Council, six in Germany. Things seem to have quietened down a bit since then!
I thought I would put in an example of an unusual sort of photography, inspired by Clerk Maxwell's demonstration in 1861 of three colour light, which in time became the basis for colour photography. Some more of these photographs can be found on my website, http://www.georgepollock.co.uk, under the title "Tri-Chromatic Shadows". For the last few months I have been improving the original slides in Photoshop, and the results seem to me to quite amazing. What do others think?
Bother! can't seem to move the file to this site. Will ask mike F to for me.

Image now added, as requested.

Hi George

Welcome to the forum and thanks for your reminisces of the older days of the club. It has been a while since we have been able to attract dignitaries such as Lord Goodman.

I have been looking at your image for a while and find that it is growing on me. It took a short while to work out was going on, before I realised you were using subtractive colour for the shot. Maxwell Clerk, of course, used additive colour comprised of red, green and blue* for his demonstration of colour photography in 1861. That indeed did become the standard first for colour film and then digital cameras later on, but not printing which uses cyan magenta and yellow. All very confusing.

* It proved the principle of colour photography, although understandably Clerk Maxwell was limited by the materials he had available at the time. The plates he was using were not sensitive to red and green was little better, so the resulting image was more like a coloured photograph than a true representation of the subject. Nevertheless, he was a true pioneer.

Hi George, thank you for taking the time to post.

I must admit when I first saw your image there was something about it that niggled at me. Although I assumed from your description there was perhaps a more technical element at play than I first may have realised it wasn't until I did a bit of digging into Maxwell I realised what it was you were attempting with the photograph! I wasn't aware of Maxwell's influence on photography, I only knew about his impact on physics!

Anyway, after I finished my research and looked at your image a little more I've figured out what it is that was niggling me! I am assuming you are either creating the shadows using monochromatic light from different angles (as opposed to coloured "shadows" in photoshop) and exploring the resulting shadows caused by the superposition of each of the different colours of light at any given point. However, shouldn't the addition of red, green and blue light create a white rather than a black shadow? How did you create a black shadow using only three colours of light?

Actually now I've posted and looked again I can see you are not in fact using RGB light but CMYK - I'm now curious why you used these colours rather than RGB light? Also, adding a primary to an opposing secondary, as is seen in the image, should still produce white light and not black (which is the absence of light). I'm now more curious what your lighting setup was to achieve this image!

davidc wrote:Actually now I've posted and looked again I can see you are not in fact using RGB light but CMYK - I'm now curious why you used these colours rather than RGB light? Also, adding a primary to an opposing secondary, as is seen in the image, should still produce white light and not black (which is the absence of light). I'm now more curious what your lighting setup was to achieve this image!

With RGB, mixing all three colours together produces white, while with CMY all three colours result in black as in George's image. Except that when printing the black is more like a muddy brown, which is why every printer has a dedicated black, hence CMYK. Since there are two colours which have the same initial, blue being the other of course, black became K.

Using RGB additive colour for taking and viewing colour images on a monitor and then printing them with CMYK subtractive colour can cause problems with colour accuracy, since tones are comprised of different underlying colours in each method. These days computer applications such as Photoshop to handle the conversion make life much easier, but it is a real issue when the process is entirely analogue from film to print.

This is based on the assumption that George's image is entirely based upon light and NOT pigment. In other words we're dealing entirely with additive colour mixing rather than subtractive that you get with pigment.

If you mix a primary with it's "opposite" secondary you get white.

For instance, cyan is created by mixing blue and green, i.e. B + G

So if you overlap red with cyan you get

R + (B + G) = White

The same holds true for mixing any primary with it's opposing secondary therefore I would expect to see SOME white light in the image. My suspicion is the image is either generated in photoshop (unclear from George's comments as to whether it's fully or partially photoshopped but he refers to slides which suggested to me it was created using light and not pigment/photoshop in the first instance) and the anomalies in the image which to me suggest this is not a straight up photograph.

For instance the "bum" of the shadow shows yellow and red overlapping to create blue which isn't possible (blue being a primary) as well as red and yellow feet overlapping bottom left and not seemingly mixing at all.

All of this leads me to believe the image isn't produced photographically using light addition and is instead perhaps created using pigmentation (subtractive) or, based on the anomalies, created/manipulated to some extent in photoshop.

After my last post, I got to wondering why we make life difficult for ourselves by taking photos and viewing the results on screen using RGB colour, but outputting prints using CMYK. Would RGB(K) not be a better solution? (In theory, the black is not required in either method, but is there for two reasons. Pure black cannot be achieved due to imperfections in ink formulations, but there is also an economic imperative. Creating black requires more than one colour to be laid down on the paper, so having a dedicated black saves on costs.)

The answer seems to be how light acts in different circumstances. When taking an image, we are seeing reflected light, but when viewing prints the colours we see depend on how much light is absorbed by the combination of inks on the paper. Since the RGB colours are quite dark, i.e. already absorbing a lot of light, it is not possible to create lighter tones when more light has to be reflected. CMY is used as these colours are lighter, although it cannot produce such a wide range of tones compared to RGB.

This website has a fuller explanation.

http://shutha.org/node/815