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mantra 08-18-2015 10:40 AM

neutral black and white adjustament layer
 
hi

i'm looking for neutral values (reds yellows greens cyans blues magentas ) about photoshop black and white layer

i have found in this forum neutral values but i lost them

for example with these neutral values , an black and white adjustament layer set to luminocity doe Not add contrast to the image , leave the image intact

thanks

AKMac 08-18-2015 12:43 PM

Re: neutral black and white adjustament layer
 
If I understand your question correctly, you would need something close to Perceptual. The numbers I use for that are R46, Y97, G84, C88, B14, M49 It doesn't always get me 100% accurate - but it's fairly close.

PS Edited. The above numbers are wrong - it should be R31, Y88, G58, C72, B10, M40.....which are fairly close, but not 100% accurate.

redcrown 08-18-2015 05:32 PM

Re: neutral black and white adjustament layer
 
The numbers AKMac gives for a B&W adjustment layer are good. Probably as close as you can get using the adjustment layer.

For a perfect "neutral" just add a solid neutral filled layer set to Color mode. Fill the layer with black, white, or any shade of gray - does not matter. Stamp visible a new layer on top of that. Set it to Luminosity mode. Delete the fill layer. Toggle the B&W Luminosity layer on and off to see there is no difference.

mantra 08-18-2015 11:43 PM

Re: neutral black and white adjustament layer
 
1 Attachment(s)
Quote:

Originally Posted by AKMac (Post 328169)
If I understand your question correctly, you would need something close to Perceptual. The numbers I use for that are R46, Y97, G84, C88, B14, M49 It doesn't always get me 100% accurate - but it's fairly close.

PS Edited. The above numbers are wrong - it should be R31, Y88, G58, C72, B10, M40.....which are fairly close, but not 100% accurate.

HI
I found these values maybe you can try them

AKMac 08-19-2015 01:08 AM

Re: neutral black and white adjustament layer
 
@MANTRA

I tried your numbers and they seem to be 100% accurate.

Please ignore my previous suggestions.

klev 08-19-2015 05:08 AM

Re: neutral black and white adjustament layer
 
Quote:

Originally Posted by redcrown (Post 328174)
The numbers AKMac gives for a B&W adjustment layer are good. Probably as close as you can get using the adjustment layer.

For a perfect "neutral" just add a solid neutral filled layer set to Color mode. Fill the layer with black, white, or any shade of gray - does not matter. Stamp visible a new layer on top of that. Set it to Luminosity mode. Delete the fill layer. Toggle the B&W Luminosity layer on and off to see there is no difference.

Your suggestion would give the average of the 3 trichromatic values assigned to each one so
r = g = b = (r + g + b) / 3

You wouldn't program it that way, but that's the result of the arithmetic. The question is actually interesting, because it makes me wonder if there's a unique combination that would yield this across any image. I doubt it, but I want to test it later.

I'm looking at its defaults, and it seems to be relying on oppositions to make something they think of as neutral. I get the defaults
r 40 y 60 g 40 c 60 b 20 m 80

It seems to treat primary wavelength colors as opponents to corresponding pigment colors that would be used to create that color.

m + y - r = 80 + 60 - 40 = 100
c + m - g = 60 + 80 - 40 = 100
c + y - b = 60 + 60 - 20 = 100

I'm not sure there's a precise neutral basis though. It seems as if it's dependent on the content. I'm not positive, because I rarely use the tool and haven't bothered to test it.

mantra 08-19-2015 09:45 AM

Re: neutral black and white adjustament layer
 
Quote:

Originally Posted by AKMac (Post 328178)
@MANTRA

I tried your numbers and they seem to be 100% accurate.

Please ignore my previous suggestions.

Hi Akmac
perfect , i have lost them
i spent some time to find them out

cameronrad 09-02-2015 06:11 AM

Re: neutral black and white adjustament layer
 
Channel Mixer:

Monochrome: Checked
Red: 30
Green: 59
Blue: 11

Black/White Adjustment Layer:

Red: 30
Yellow: 89
Green: 59
Cyan: 70
Blue: 11
Magenta: 41

Photoshop calculates luminance by a weighted average of the three channels The weighting assumes that green represents 59% of the perceived luminosity, while the red and blue channels account for just 30% and 11%. Since Cyan is the compliment to the Red channel, you can calculate the Cyan value by taking 100(%) and subtracting the Red and likewise for the other channels. For instance for Yellow, 100% - 11% (B) = 89%

mantra 09-02-2015 11:12 AM

Re: neutral black and white adjustament layer
 
Quote:

Originally Posted by cameronrad (Post 328314)
Channel Mixer:

Monochrome: Checked
Red: 30
Green: 59
Blue: 11

hi
yes ! great :bigthmb:


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