Autochrome Conversion

This Autochrome conversion tutorial aims to simulate the first practical colour photography process.

Devised by the Lumière brothers in the first few years of the twentieth century, the process brought the recording of colour images within reach of those few rich enough to afford it.

More importantly it brought a view in amazing (at the time) colour of 1900s life within reach of later generations.

An Autochrome image is instantly recognisable and it's these distinguishable features which this Adobe Photoshop tutorial aims to replicate.

There are many different paths to achieve this effect in Photoshop as well as in other software packages.  

As a matter of fact, you will find a tutorial covering a method using PaintShop Pro elsewhere on this site. 

This is the Photoshop version of an Autochrome conversion.

This is an Intermediate level tutorial so you will need to have some familiarity with ...

  • Adjustment Layers
  • Blending modes
  • Channels
  • Filters

You will need

  • Adobe Photoshop.

  • A suitable image. Since many Autochromes were of still-life or non-living objects which were stationary, this would seem to be a place to start. The sensitivity of the medium was low and exposures could be long. Sunny conditions were often recorded and fortunately this increased the contrast of what was inherently a low contrast medium. There are portraits made in this medium but they show the staid composition associated with long exposures.

Autochrome Conversion Look

The characteristics we aim to emulate

  • Low contrast because the medium was quite thick and the starch grains absorbed much of the light; and the image is viewed by transmitted light. The dyes have degraded during the years leading to a slightly faded look as the dyes used to record the image are the very same dyes which are used to view the image. The original silver from the chemical development of the silver halides in the film remains in the film.

  • A slight lack of sharpness because of long exposure times and subject/camera movement.

  • A grainy texture because the colour filter in front of the recording photographic emulsion was made from potato starch stained in supposedly Red, Green and Blue dyes and the mixture of these grains dispersed evenly. The dyes were red-orange, green and blue-violet. This sequence of dyes leads to red and orange being overly saturated.

  • A slight magenta (purple) cast because the dyes were not perfect and transmitted a range of colours rather than clear cut.

  • Enhanced red and blue saturation, especially red because of the imperfect dyes and the greater sensitivity of the emulsion to blue light.

  • A warmer rendition because many photographers used a yellow to orange filter to diminish the over sensitivity of the emulsion to blue light.

Getting Started - choosing the right image

So why do you want the right image?  What you want is an appropriate image.

Autochromes were exposed for a couple of seconds; what you don’t want is a dynamic subject obviously exposed by a high tech camera at a high speed; what you might consider is a static subject or one which just might hold still for a couple of seconds.

Portraits of Grown-ups, still life and landscapes usually figure highly in Autochromes from the days gone by. Sunlit with low contrast is what works well. Reds and blues figure significantly. High tech glass facades might not have the right genre or era but break the rules as you wish.

We spend a great deal of cash of achieving ever finer detail and quality from our digital equipment and more on software which removes noise and pixel degradation, so why introduce a soft, grainy, low contrast image with a colour cast to our repertoire?

In terms of the psychology of imaging the grain is rounded as in analogue film and not square edged as in pixels. There are ‘gaps’ in the information between the grains and our brains work harder to create the missing parts of the image. This is the Gestalt Principle of Continuity.

The image I chose for this Autochrome conversion is a  warehouse in Manchester, UK, on the canal network. This would have been a very busy place at the time of Autochromes.

Mouseover the image to see the difference between the original and the converted image.


Autochrome Conversion Steps

Step one – Contrast control

It’s always good practice to work on a copy of the original image layer, so duplicate the background layer.

Layer > Duplicate layer

The histogram shows that the image is not too contrasty so we may just get away with the contrast as it is. The curve sits in the middle of the graph and there are no lost pixels at either end, otherwise ...

Image > Adjustments > Brightness contrast or ...

Finer adjustments can be made using Image > Adjustments > Curves

Step two – the sharpness control

You don’t need to make the image blurry; just take the edge off the sharpness. For my approximate 4500 by 3000 pixel image, blurring of 1 to 2 pixels is enough.

Filter > Blur > Gaussian Blur

Step three – the grainy effect

You’ll need to see the channels panel - Windows > Channels will expose it.  This gives you access to each of the colour channels (Red/Green/Blue).

Click on the blue channel to add grain to that channel by Filter > Noise > Add Noise.  For the image I selected, 50% addition to the blue channel is sufficient.

Using the channel panel click onto the Green channel and add 40% by the same process.

Using the channel panel click onto the Red channel and add 30% by the same process.

Of course you may decide to make some changes to the suggested values.

Finally click onto the RGB channel to reveal your work so far.

Step four – the colour balance control

Now we can add a slight magenta cast to the image. Not all Autochromes exhibit this. You may decide to omit this step.

Layer > New Adjustment layer > Curves and click OK when it appears.

In turn select the red, blue and green curves and ever so slightly at the centre of each curve, bend ...

  • The red curve up
  • The green curve down
  • The blue curve up

Step five – the saturation adjustment

Now add a saturation adjustment using Layer > New Adjustment layer > Hue/Saturation.

Click the dialogue box OK when it appears.

Add about 30 units to the red value and slightly less to the blue

Step six – warming the image

Not all Autochromes show warming. But here’s how to achieve it.

Layer > New Fill layer > Solid Colour

Click the dialogue box OK when it appears.

Choose a warm orange/yellow.

Change the blending mode of the layer to Overlay and the opacity to about 50%.

And there you have it – an Autochrome conversion.

You can add ‘damage’ to age the image or a border – but that’s personal taste and outside the scope of this tutorial.

Here's the end result - give it a try ...

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