how can i emulate a film red filter? and strange issue

[JohnVo]

hi

well i like to emulate a film red filter for my black and white with a solid color adj layer set to color

i have my photo in color , and add several adjustaments layers , and the last adjust a gradient in many cases

but i have noticed that if i use color mixer or black and white (both with this settings) or gradient (all blend normal mode) , the solid color doesn't affect

well some screenshots

if i use a gradient

or

channel mixer with these settings

or a black and white with this settings

well The SOLID Color adjs does Not affect the image , it could be red , blue , yellow , it doesn't matter it doesn't affect the last image

but if i use a hue/saturation adjust like this , at the top , changing the solid color change the black and white

may i know why?

but is i use channel mixer and black and white with ps settings the solid color change the black and white , Not the gradient

or

can somebody please try to add a solid color and a channel mixer or black and white adjustmants laywer on top , and change the solid color from red to blue or other color and see if can impact on the last layer?

it's very weird

thanks

[davescm]

Hi

First the question of do I see a change if I put a black and white adjustment layer above a sold color layer set to color - yes I do

But..

A solid color layer set to Red and color blend mode does not emulate a red filter.  A red filter allows through red and does not allow Blue /Green i.e it subtracts blue /green.  A red layer set to color blend mode changes the Hue & Sat of Blues and Greens to Red. That is not the same as subtracting them.

To simulate a red filter use the black and white adjustment layer and turn down the non red content

Dave

[JohnVo]

hi

try to use these value on the black and white adjustament layer live the 3 screenshot !!!!

these value

reds 30

yellow 89

green 59

cyan 70

blue 11

mage 41

it will create a neutral black and white and try again with the solid color

[davescm]

Giovannivolontè  wrote

it will create a neutral black and white and try again with the solid color

So all that is showing is that color blend mode is working correctly. The color blend mode creates a result color with the luminance of the base color and the hue and saturation of the blend color.

Your black and white layer settings give equal grey from a mid blue to that from a mid red, in short they simulate just removing the colour and leaving the luminance

As I said earlier you cannot use a Red layer with colour blend mode to simulate a Red filter.

Dave

[JohnVo]

hi

in short to emulate a photo film filter i had to use always & only (there are no other tools) black and white adjustament layer?

in silver efex pro 2 it's different , it uses the hue to create a photo film filter

thanks

[davescm]

It depends how accurate you want your emulation. Real photo filters allow through certain colours and block others so you have to subtract the unwanted colours to emulate them. Changing hue does not subtract. Targetting a hue then reducing luminance does subtract.

Dave

[JohnVo]

Hi Dave

just to make an example , how can i emulate a red film filter for black and white photos?

just some info

Project 40- Coloured Filters with Black & White Film | francessmithlandscapes

silver efex Saturday Spotlight: Black and white filters

i'm thinking to buy power retouche Convert to black and white with our Photoshop plugin

but photoshop is so powerfull , i should obtain the same result without extra plugins

thanks

[D Fosse]

...or you can use a B&W adjustment layer and set the sliders as appropriate - as Dave showed you in post#1.

[D Fosse]

If the desired result is a B&W image, there is a very simple way: Just use the red channel and discard the other two.

If you still want an RGB file with three color channels, copy the red channel and paste it over the RGB image. Merge down.

(Note - for best results you should have working gray set to Gamma 2.2, which basically matches sRGB and Adobe RGB gamma. Individual color channels are treated according to working gray - that's the gray profile that gets assigned to it).

[Chuck Uebele]

This got me interested to see if I could emulate a red filter with blend modes. Yes, just using the red channel or a black and white adjustment layer is much easier, but say you want a particular color filter. I found a way to do that following these steps:

1. Make a solid color fill layer the color you want the filter to be, and set the blend mode to color burn.

2. Create a merged-stamp-visible layer ctrl/cmd-alt/opt-shift-E.

3. Either duplicate this layer or add a curves adjustment layer and set the blend mode to Linear Dodge (Add).

As you can see from my screen shot, the left half of the image is just the red channel, the right half is my process, they are identical, This seems to work with any color, so you're not limited to the colors of the channels. B&W adjustment layer is still far easier!