Black & White Conversion Question
Hello –Â
I have a question for those who are familiar with the B&W conversion panel: In both PS and Aperture, I always used the channel mixer for b/W conversion, for the simple reason that I somehow intuitively understand what it's doing, as it pretty much follows the logic of what you'd be doing in the lab back in the analog days.
I cannot fully figure out the logic of the RYGCBM-Mixer. E.g. it gives you a properly balanced image already at all sliders set to zero, which means these values seem to be relative or assigned to a certain value that's considered "normal", instead of meaning e.g. "zero red channel". What does the Zero value of each slider correspond to?
And for instance, if I want to to a red, green or blue-channel only conversion, what do I do?
(Yes, I understand the basic logic of the sliders, that you can increase or decrease the conversion's sensitivity for red, yellow etc.)
Thanks for any hint on this!
I have a question for those who are familiar with the B&W conversion panel: In both PS and Aperture, I always used the channel mixer for b/W conversion, for the simple reason that I somehow intuitively understand what it's doing, as it pretty much follows the logic of what you'd be doing in the lab back in the analog days.
I cannot fully figure out the logic of the RYGCBM-Mixer. E.g. it gives you a properly balanced image already at all sliders set to zero, which means these values seem to be relative or assigned to a certain value that's considered "normal", instead of meaning e.g. "zero red channel". What does the Zero value of each slider correspond to?
And for instance, if I want to to a red, green or blue-channel only conversion, what do I do?
(Yes, I understand the basic logic of the sliders, that you can increase or decrease the conversion's sensitivity for red, yellow etc.)
Thanks for any hint on this!
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Come on, someone has to know about this! 0 -
[quote="Flow_Berlin" wrote:
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And for instance, if I want to to a red, green or blue-channel only conversion, what do I do?
I feel that you for the most part already answered your own question. The slider's zero position is relative.
Going to the highest negative value for all colors except red and highest positive value for red, gives you a red-channel only conversion.0 -
Paul, thanks for your answer.
Unfortunately, that setting you described (all sliders to -100, red to +100) does not produce a red-channel conversion, I just checked.
Also, it would be helpful to know what position in the channel mixer does a "0 for all sliders" corresponds to, i.e. what mix does the default (zero) setting of the B&W tool produce?0 -
Some pointers, that I hope will lead you in the right direction:
With the BW sliders at zero, you have the same bw-conversion as you have with the Saturation slider.
If you want to match the default BW conversion of CO in PS, you can use R 30%, G 60%, B 10%. This conversion is similar to YUV, http://en.wikipedia.org/wiki/YUV#Conver ... 2Ffrom_RGB.
The logic behind the BW-tool is not to match the PS Channel Mixer, but instead to match the logic behind using tinted filters with BW Film or BW sensor (such as our Achromatic series digital backs).
So if you would like the effect of using the yellow filter, you should decrease all sliders but the Yellow slider.0 -
Thanks for your reply, Christian!
The tinted-filters logic is exactly what I'm trying to understand or translate to the B&W tool. To my understanding and memory from the days with analog, using filters on a B&W film is essentially like using the corresponding "channel"/filter in printing a B&W print from a color negative (minus the specific sensitivities of B&W films, of course). Am I confusing something? This is essentially what the PS channel mixes tries to recreate.
Meaning, a B&W image taken with a red filter resembles as a red-channel-only B&W conversion of a color image. Yellow filter on-camera is the same as yellow "channel", which is 2/3 green plus 1/3 red. And so on.
Now, I could recreate the 30/60/10 setting, which is in fact very close to the effect of a yellow filter on-camera.
However, the recipe you mentioned:[quote="Christian Gruner" wrote:
The logic behind the BW-tool is […] to match the logic behind using tinted filters with BW Film or BW sensor […]. So if you would like the effect of using the yellow filter, you should decrease all sliders but the Yellow slider.
does not at all reproduce what one would get using a yellow filter or a yellow "channel" conversion, but instead looks dramatically different:
http://www.flowtographyberlin.de/images/external/CO-BW-Tool-Comparison.jpg
Following the same logic you described, I should be able to get a red-channel/filter conversion by fading out all but the red slider, which is also not the case.
How can I achieve classic conversions (like those with filters) with the B&W tool? There must be a logic behind these sliders that somehow connects to classic photography or is in some other way comprehensible, I can't imagine that e.g. all PhaseOne users just fiddle around with the sliders until they feel it's right.0 -
There are also a lot of presets. On the Colour Tab (or on the Black and White tab if you choose to show it) there is a tool labelled Black and White. On that, select the check box for "enable black and white". Then there is a long list of presets you can choose (click the little symbol with 3 parallel lines). For example you could choose several strengths of yellow filter. Choose one and watch what happens to the sliders. On Yellow Filter 3 for example, all the sliders stay in the centre except for Cyan and Blue which go down to -40 and -56 respectively. (This does indeed connect with classic photography. A yellow filter would let the yellow through and cut out the Cyan and Blue to some extent.) If you like the look from one of the presets, well and good. Or you can try playing with the sliders a bit - what happens for example if you bring the Cyan slider down even more, or pull the yellow slider up a but more? If you get a look you particularly like, you can even set it as a preset of your own.
So I don't think that we all fiddle with the sliders until we are happy. If I want a B & W conversion, I try running down the list of presets until I get one that I think I might like, in conjunction with also perhaps adjusting the contrast etc from the value I would have used had I been processing the shot for a colour output. I rarely fiddle further with the colour sliders, but of course you could. (I'm more likely to play with the sliders to adjust the strength of a split tone effect, but that is another story.)
Ian0 -
Ian, thanks very much for your post!
Yes, I've seen those presets, and it's true, the "Yellow Filter" preset outputs the same thing as a yellow (i.e. red+green) "channel" conversion.
Anyway, I think it's a bad thing to be dependent on presets (and yes, to somehow be able to follow), but to not to be able to recreate the thing yourself, because you haven't understood the way it works – which is what I'd be doing now. E.g. there's no preset for blue filter (there is one for tinting the image blue), red filter, green filter, all that.
I guess what I find most confusing is the mixture (no pun intended, haha) of additive and subtractive logic. I.e. the YMC colors would be the color of the filters used for producing the RGB positive, while RGB are the additive logic (i.e. in producing the YMC negative). (Well, filters are always subtractive, but you get the idea.)0 -
[quote="Flow_Berlin" wrote:
Ian, thanks very much for your post!
Anyway, I think it's a bad thing to be dependent on presets (and yes, to somehow be able to follow), but to not to be able to recreate the thing yourself, because you haven't understood the way it works – which is what I'd be doing now. E.g. there's no preset for blue filter (there is one for tinting the image blue), red filter, green filter, all that.
I suppose that you could study what the other presets do (say yellow and red filters) and figure out what you'd need to do to create the effect of a blue filter. Presumably you'd reduce the red and yellow sliders.
Ian0 -
[quote="Ian3" wrote:
I suppose that you could study what the other presets do (say yellow and red filters)
In my preset list, there's only one actual filter preset type, and that's Color - Yellow Filter 1 through 3. No other filter presets, the rest of the color-named presets are in the Toning category. (Theres yellow-red, too, but well.) No red, no green no blue. So nothing to study, unfortunately.0 -
[quote="Flow_Berlin" wrote:
[quote="Ian3" wrote:
I suppose that you could study what the other presets do (say yellow and red filters)
In my preset list, there's only one actual filter preset type, and that's Color - Yellow Filter 1 through 3. No other filter presets, the rest of the color-named presets are in the Toning category. (Theres yellow-red, too, but well.) No red, no green no blue. So nothing to study, unfortunately.
Oh yes, you're right. Only the yellow ones say filter.
Ian0
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