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neutral black and white adjustament layer

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  #1  
Old 08-18-2015, 10:40 AM
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mantra mantra is offline
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Question 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
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Old 08-18-2015, 12:43 PM
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AKMac AKMac is offline
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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.

Last edited by AKMac; 08-18-2015 at 04:18 PM. Reason: Wrong Information
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Old 08-18-2015, 05:32 PM
redcrown redcrown is offline
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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.
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Old 08-18-2015, 11:43 PM
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mantra mantra is offline
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Re: neutral black and white adjustament layer

Quote:
Originally Posted by AKMac View Post
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
Attached Images
File Type: jpg black and white neutro.jpg (50.4 KB, 61 views)
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Old 08-19-2015, 01:08 AM
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Re: neutral black and white adjustament layer

@MANTRA

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

Please ignore my previous suggestions.
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Old 08-19-2015, 05:08 AM
klev klev is offline
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Re: neutral black and white adjustament layer

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Originally Posted by redcrown View Post
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.
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Old 08-19-2015, 09:45 AM
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Re: neutral black and white adjustament layer

Quote:
Originally Posted by AKMac View Post
@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
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Old 09-02-2015, 06:11 AM
cameronrad cameronrad is offline
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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%
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Old 09-02-2015, 11:12 AM
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mantra mantra is offline
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Re: neutral black and white adjustament layer

Quote:
Originally Posted by cameronrad View Post
Channel Mixer:

Monochrome: Checked
Red: 30
Green: 59
Blue: 11
hi
yes ! great
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