Mixed ink changing colour

Hi everyone,

I have another question for you all. Everyone has been so helpful so far and saved me months of trial and error.

I’m not sure if this issue has been addressed previously, if it has perhaps someone could redirect me to the original discussion.

I’ve been mixing ink the last few weeks. I don’t use transparent white, I use opaque white because I find it easier to reach the shades I want. I mixed a blue, raspberry and light pink shade. I was at a wedding fair showing my letterpress invitation and bought the ink with me in glass jars to show people that I mix the ink myself. I had the ink jars in bright light for two days.

When I got home after the second day, I noticed that the light pink ink was turning yellow. Does anyone know why? Is it light exposure, oxydization or something? Is it the glass jars I’m storing them in? The are glass with air tight rubber tops.

Thank you in advance,


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Many red pigments are “fugitive”, meaning that they are easily faded by light, the brighter and more UV-strong the light the quicker the fading. Reds tend to fade more quickly than other colors. I suspect that the red pigment used in your mix is one of the more sensitive ones, and that the color is a light pink indicates there is less of the red and thus the fading will be noticeable quicker. That’s my guess!


Thank you Bob. I thought it was the light also.

This may be a silly question but I’m worried that when my invitations are printed, they could change colour. Is that possible?


They could — if extensively exposed to light, because it’s the cumulative exposure that causes the fading, which shouldn’t continue in the absence of light. So if the printed invitation is left on a sunlit table, it will fade, but if it is in its envelope in a drawer it won’t.


You can test the fade resistance of your inks by covering up one half or your solid image with dense black paper and then leave in sunlight for several hours, a week or more.
Then remove the mask and see if it has changed between the two areas. If you leave it longer you may see even more fading.