Color correction for thoriated lenses

[jlovda]

I have many slides that used my Canon FD 35mm f/2 lens (w/ the concave front element). It used thoriated glass and the pictures have a distinct yellow/brown cast to them. I have fiddled with some of the PSP2020 color adjustments but can't neutralize the color. Does anyone have a "formula" they use to correct this? It seems to be a well known problem but I have never seen a fix.

Thanks

https://www.flickr.com/photos/79976134@N07/16708441449/

[hartpaul]

Try Fade Correction Adjust > Color > Fade Correction

Then White Balance Adjust > White Balance and use the Smart Select by zooming in to the conductors white color and clicking on that . You could also try Levels to improve the contrast a bit.
Looks like was taken on an overcast day (no shadow for conductor) so would expect it to be a bit on blue side.

[migf1]

Good tips by hartpaul!

You may also try the Curves or Levels Auto buttons: https://gyazo.com/2cef1edff8fc02be33f8e40cfedbd5e6 (you should Reset it before trying a different button). The Contrast button affects only the Luminocity (lightness), Color button affects only the Hue & Saturation, and Levels button affect all 3.

However, if you like to have a more precise control and you don't mind going a little more advanced, have a look at this video: https://youtu.be/QhPteAOSe3U

It goes a little crazy for marking the exact 50% gray, black and white points, but if you already know which areas on your photo should be neutral gray (or black, or white) you can skip directly to the 1-point or 3-point correction sections of the video (there is a timestamps index-table in the description of that video, select SHOW MORE to see it).

The gray point is usually giving the more balanced colors, but try also black or white points. Also try more than 1 areas on your photo for each point (again, you have to Reset after each try).

Nice photo btw!

[jlovda]

Thank you all! I have a lot to learn here so it's now time to roll up my sleeves.

John

[TimW]

After doing what migf1 suggested, go to HSL (Hue, Saturation, Lightness), and bump up the red colors to about 40 or 50.