Early Colour Photoghraphs

Between about 1895 and 1935 there were many similar methods which used integral filter screens for producing colour photographs, i.e. the filter screen which produced the image was the one which stayed present and was used for viewing the final image.

The screen in early colour photographic methods was made from a pattern of some combination of red, orange, yellow, green, blue, and purple dots or lines (not all together in any patented process).  Perhaps the most famous of these is the Autochrome which is featured in several tutorials on this site.

When you have investigated one method for other early colour photographic methods, you could design your own screen and process and test it.

The filter screen in other early colour photographic methods allows the black and white film emulsion to be exposed to the components of the full colour spectrum.  When the film was developed, the screen remained in the film and as the film was illuminated the varying intensity of light gave the impression of a colour image.

The problem with ruled or dot screens is that the repeated pattern produces a Moiré or similar effect which is like looking through net curtains or at a 405 line CRT TV screen of the 1960s.

The stages we have to synthesise are:

  1. The construction of a colour screen
  2. The separation of the image into colour components
  3. Application of the filter to the colour component layers
  4. Minimising the Moiré effect – a pattern resulting from the dots and lines of the screen combining with any similar sized patterns from the image.
  5. Recombination of the layers to make an image.


The early images were not as true to the original colours as would be produced by colour photographic methods of today, so we will need to adjust 

  • The sharpness
  • The colour balance
  • The contrast
  • The brightness

of the final image.


This is an intermediate level tutorial, so you will need to be familiar with

  • Levels
  • Layers
  • Curves
  • Blending modes

You will need

  • A colour image on which to work
  • PaintShopPro (I’m using X8)


Choosing the image

These types of colour process were only current in the early twentieth century and so pictures show mainly still life, landscape and posed figures.  Moving objects do not figure highly.

You may want to adjust the image using levels, curves or basic adjustments before starting the process.


This image was not a straight from camera image – it was an HDR image derived elsewhere.

Step One – making the screen

In the Autochrome process the built-in screen which makes the 3 colour separations for Red, Green and Blue are random grains of dyed potato starch.  In a raft of similar and synchronous processes, dyed and ruled screens can have regular patterns within them.  What we need to do, is to copy their tessellated (repeated use of a single shape, without gaps or overlapping) structures.  The screens are microstructures almost at pixel level.  Therefore our screen pattern should be of comparable size.  We achieve the screen by making a pattern in PaintShop Pro.  

Open a new file in PaintShop Pro File > New

The blank image should be no bigger than 50 x 50 pixels, white or transparent background, 300ppi, raster, 16 or 8 bit RGB.

If you look at the screens which were made in the early days, the ones which were ruled onto the film had regular patterns, unlike those for the Autochrome (and a few others) which were random colour dots.  What we need to do is to make a simulated screen of a regular pattern.  The one I chose for a matrix has a blue background onto which red and green dots are regularly placed.  So the repeating pattern or simplest recognisable pattern is made from two blue dots and one red dot and one green dot.  Then that four dot pattern over 10 pixels by 10 pixels can be picked up by copying and pasted to repeat the pattern over the 50 pixels by 50 pixels square to form the pattern for the fill. 

Similarly, the line matrix is made from a repeating pattern of a red line and a green line and a blue line each of 10 pixels width running the length of the pattern which can be copied and pasted to give a 50 pixels by 50 pixels square to form the pattern for the fill. 

So to make the pattern for the fill for PaintShopPro to fill using the paint bucket later, you need to make a small square image; put a small pattern in it; copy the pattern and then fill the remainder of the square.

File>New

The blank image should be no bigger than 50 x 50 pixels, white or transparent background, 300ppi, raster, 16 or 8 bit RGB.

The repeating pattern should be applied with a brush and individual pattern components should be no bigger than about 5 to 10 pixels. TIP – make one pattern group; select it using a rectangular marquee tool; copy it CTRL-C; and use CTRL-E to paste it in as a selection, and repeat this until the image is filled.


You can use the pattern as it is, but it’s better to soften them otherwise you can get odd repeating striations in your final image.

Adjust > Blur > Blur

Or 

Adjust > Blur > Gaussian Blur with a 1 pixel blur will suffice.


GAUSSIAN ONE MATRIX

Save the file in

………\Documents\Corel PaintShop Pro\18.0\Patterns as a JPG file.  

The file is small, so maximum quality will be quite OK.  Choose a file name you will recognise later.

Here’s an example of a line based screen in its blurred format.


GAUSSIAN ONE LINE MATRIX

Step Two– making the colour separations

If you have not already done so, load the image you intend turning into a replica of another early colour photographic method. 

Obtain the individual channels of the image Image > Split Channel > Split to RGB

Select the tab for one of the colours; they will be labelled as something like red1, green1, blue1.

Add a new layer Layers > New Raster Layer

Set the parameters Blend to Exclusion; opacity to 100%.  Note that this blend makes a softer, low contrast final image.  If you set the Blend to Difference you will get a slightly harder, higher contrast final image.

Step Three – modifying the separations

Double-click the materials palette to bring the dialogue box for the properties of the foreground colour.

Choose pattern and the selection box appears containing the loaded patterns.  If you’ve chosen the correct place in which to save your pattern, it should be present to be selected.

Use flood fill to add your filter to the channel.

Now for each of your two other channels repeat the process of adding the layer (correct parameters); flood filling the layer.


Should you choose a line screen the moiré effect will be noticeable at this stage.


Step Four – making the final image

Recombine the layers - Image > Combine Channel > Combine from RGB (check that the correct colour layers are allocated to the combination channels i.e. red is allocated to the red channel.

Many of the examples of other early colour photographic method images are high in green content.  If you adjust the opacity of the fill layer for the green channel to a value between 70 and 100% you can achieve this before you make the make the recombination.

Here’s the image reconstituted using a line filter/screen


From the matrix filter/screen


If you use the Difference blending mode rather than the Exclusion mode you can see a contrast difference.

So have try at making a filter pattern to simulate another early colour photographic method.  Then make a tessellated filter of your own.


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