< snip >
> Decompose you image to RGB components.
> In the new image, hide the red and green layers.
> Add a layermask to the blue layer, initialized to a "Grayscale copy of
> the layer".
> Fill the blue layer with black.
> OPTIONAL: Most orthochromatic film would respond to some extent to
> green, so repeat the last two steps on the green layer, make it
> visible, and set its opacity to a relatively low value (0-30%).
This is very interesting and to a learner like me not too complicated.
Perhaps I did not do it quite right but I have what appears to be an
overlay of small black and white squares. How do I get rid of that?
> This method is a bit crude, but should provide something not entirely
> unsuitable. A more accurate approach would probably entail applying
> appropriate curves to the different color channels.
Crude or not it looks very effective and a good starting point. Thank
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