Seems pretty simple to me. I agree they didn't explain in a friendly way. C is the result. easy. It's per-channel. That is, for 'Darken', the resulting value in a given channel is either A[channel] or B[channel] depending on which of A and B's value for that channel is lower. For example
if
A = #00ff88 hex
B = #448822 hex
then
combined C = #008822 hex
for 'darken' mode

A is the overlying pixel value, that is being 'applied' to B, which is the underlying pixel value.

As to the specific blending mode, 'vivid light', You will need to look at which of GIMP's modes correspond to Color Burn/Dodge, create a layer for each,
and normalize the color values from the ranges 0..127, 128..255 to
0..255,0..255
(hint: filling with #7f7f7f, Divide mode, doubles the color values)

before partially applying each layer to the destination layer.

This partial appllication is the tricky part. For each channel, you want to apply the burn layer where the values are

(It would be almost trivial to implement this as a GEGL op, which is something you could consider for the future.)

I think you just miss the"Glossary" at the right side of the linked page Anyway David Gowen explained well

i just want add another link that may be useful Pegtop delphi
I want to write a plug-in for gimp 2.4 that will emulate the PS "Vivid Light" blending mode. I've found some formulas for the PS modes, but I don't know what the variables are and how they would map to gimp function use. The formulas are at:

http://www.simpelfilter.de/en/grundlagen/mixmods.html

Basically, I need a guide to 'C', 'A' and 'B' for the complete idiot. Any help would be greatly appreciated.

TIA,

Jim

Alchemie Foto\grafiche
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ooppss

for some reason my message was reformatted ,(quote tags and link removed) in a way it make no more sense

i wanted just add this link http://www.pegtop.net/delphi/articles/blendmodes/

and point out that on the page quoted on www.simpelfilter, there is a glossary on right side that make everything more clear

sorry for the confusion

Alchemie Foto\grafiche
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The simpelfilter url works for me as is. Also .. I'm confused. Didn't you provide that URL in the first place, suggesting you had been there?
Are you saying you had been there and now cannot go there?

http://www.simpelfilter.de/en/ works for me, if you are looking for the 'base' page of the site.

On Tue, Apr 1, 2008 at 11:36 PM, Jim Sabatke wrote:

I can't seem to connect to the www.simpelfilter site. I also tried spelling it www.simplefilter. Am I doing something wrong, or does the URL need an adjustment?

TIA,

Jim

i referred to the first link posted in this thread, is working http://www.simpelfilter.de/en/grundlagen/mixmods.html

i suppose you try c"com" instead then "de"..anyway page is in english

I can't seem to connect to the www.simpelfilter site. I also tried spelling it www.simplefilter. Am I doing something wrong, or does the URL need an adjustment?

Alchemie Foto\grafiche

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