Re: K2 Yellow Filter reversal?
Re: K2 Yellow Filter reversal?
- Subject: Re: K2 Yellow Filter reversal?
- From: Rick Gordon <email@hidden>
- Date: Mon, 24 Nov 2008 11:15:14 -0800
A quick web search is not finding confirmed values for a Wratten #8 Yellow filter, but I'd start with this:
1) Add a Photo Filter adjustment layer. (This will only be available for RGB images.)
2) Choose Yellow. (I don't know that this is meant to match a Wratten #8, but it's the best place I can think of to start experimenting, without documented Lab values.)
3) Click the yellow swatch in the dialog,
4) Note the Lab values, and change the a and b values to the inverse of their current values. The color should now be a light blue, which we hope will neutralize the effect of the yellow filter.
5) Adjust the filter opacity to its most desirable value, and note if at that point, you'd want to adjust the "a" value (the scale from green to magenta, roughly) and/or the "b" value (the scale from blue to yellow).
6) If so, adjust the Lab values accordingly. More negative values will make "a" more green and "b" more blue; more positive values will make "a" more red and "b" more yellow.
7) Repeat steps 5, and 6, if necessary.
Rick Gordon
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On 11/24/08 at 1:44 PM -0500, J Richter wrote in a message entitled
"Re: K2 Yellow Filter reversal?":
>Thanks for the info, Rick
>
>I'm not savvy enough how to do that. I did find photo filters but it seems only canned ones are there. I'm under Mac OSX and CS3. Did I miss an option or drop down? Custom did not present me with any options. I tried to invert my curves as well with limited success. What seems to work though with good success at creating a "pleasing image" is to "match color" with a reference photo, reason being that no color info was received by the sensor of the scanner. My friend shot this as a slide 30 years ago and then scanned it recently. So we really cannot undo something that is not there. It is a good exercise along the road of education for me, so thank you!
>
>Jurgen
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___________________________________________________
RICK GORDON
EMERALD VALLEY GRAPHICS AND CONSULTING
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WWW: http://www.shelterpub.com
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