How to adjust colour by specific amount.

In Photoshop, is it possible to adjust the RGB colour of an image by specific RGB increments ?.
For example the RGB values of a specific point are 100,50,20 and I wish to globally adjust the whole image so that same point is now 120,40,25.
In other words adjust the whole image by +20 Red, -10 Green and +5 Blue.

Why ??

In many photos I like the result of the in-camera conversion to JPG and I want to apply the same conversion to my RAW so I have an uncompressed 16-bit RAW file looking (effectively) the same as the compressed 8-bit JPG image. I've looked at trying to mimic the in-camera process without much success.

So the new plan is to adjust the colour of the RAW file to match the JPG so it, at least, looks the same.
And use this as the starting point for the image editing.

Curves adjustment layer. Go to each channel and change values. Red - input 100 output 120; Green - input 50 output 40; Blue - input 20 output 25.

Many thanks, works perfectly!

Interesting. When working with RGB curves note that such an adjustment will also alter the brightness or luminance of the image - that is, color and luminance are linked in RGB. Also, by making this one adjustment to a specific RGB value you are altering all colors and tones by virtue of the spline nature of the curve.

There are a couple of ways to refine this - one is to use a raw converter that has profiles for your camera that mimic the manufacturer's various camera JPEG modes (Fujifilm calls them film simulations, canon calls them picture styles, etc). Then, you have a much more sophisticated and targeted approach to reproducing the JPEG in your raw converter than a simple targeted curve adjustment. If you need to use the curve for whatever reason, then you can switch its blend mode to "Color" in PS and limit the effect to just the color. You can also manipulate color independently of luminance by working in the Lab color model.

Kirk

Thanks Kirk,

More to think about.....

There was a reference to using the Canon software to produce a TIFF equivalent and then using that in PS. Not a lot of success with that method, yet.

Where this originated was a trip a couple of years ago to the Kimberley's - Fantastic red/orange rocks against brilliant blue sky. Looked great on back of camera and JPG import. Could not, for the life of me, match that appearance in my RAW conversion.


Steve

With a Canon camera using DPP it will default the output to match the output from the camera. IIRC it allows you to export a 16 bit TIFF if that is the way you want to go. I'm a Lightroom user, so don't often fire up DPP.

In Lr you can chose the "Camera" profiles that Adobe developed to match the same named Picture Style in the camera. Personally though I prefer the Adobe named profiles, although they do seem to match the names of the usual Canon Picture Styles. Mind you things like Landscape and Faithful are pretty universal.

Alan

joker_382 wrote in post #19232513
Thanks Kirk,

More to think about.....

There was a reference to using the Canon software to produce a TIFF equivalent and then using that in PS. Not a lot of success with that method, yet.

Where this originated was a trip a couple of years ago to the Kimberley's - Fantastic red/orange rocks against brilliant blue sky. Looked great on back of camera and JPG import. Could not, for the life of me, match that appearance in my RAW conversion.


Steve

If you use Canon's DPP to generate an RGB file from the raw Canon file, then you are getting the exact same thing as the JPEG generated from the camera, assuming you choose the picture style for which your camera is set. If they look different, it is probably because of the view you get on the tiny LCD of your camera, and its display settings, versus the view you get on your computer display and its settings - that is, it has nothing to do with the file itself.

kirk

Thanks Kirk
Did some experimenting and need to do it again in a more controlled fashion !!
Camera is set to Standard and finally worked out how to use that profile in LR. Where it got complicated is that when you use LR to open in PS you no longer have the Canon profiles available, only "Color" profile. You do have access if you open the RAW file for PS directly - which sort of makes sense but defeats the purpose of using LR.

I'm still seeing a difference in colour between a DPP TIFF file and standard JPG out of camera.
But there is still some confusion as to which profile is being used where. I kept seeing image shifts on comparison because lens correction was automatically being applied on import to LR but not RAW into PS

I really need to do a structured comparison to establish exactly what is happening where !

I'll let you know how I go.

Steve

So,

Set camera to"Neutral V2", took photo with both RAW and JPG enabled.
Opened JPG from PS, opened equivalent RAW file in PS through ACR with profile Set to "Camera Neutral V2".
ACR version has slight but noticeable colour difference to JPG version.
Image appears slightly sharper (no surprise) and colour actually looks a bit better, to my eyes.

Imported both JPG and RAW file into LR, with profile set to Camera Neutral V2, then opened both in PS from LR.
The RAW file processed through LR is slightly but noticeably different from the RAW process into PS through ACR.
This was a surprise, given it should be the same engine.
The JPG imported through LR to PS looks identical (as far as I can tell) to the JPG loaded directly into PS.

End result, will probably just stick to importing through LR and opening in PS and not try to make any more comparisons.

joker_382 wrote in post #19233381
So,

Set camera to"Neutral V2", took photo with both RAW and JPG enabled.
Opened JPG from PS, opened equivalent RAW file in PS through ACR with profile Set to "Camera Neutral V2".
ACR version has slight but noticeable colour difference to JPG version.
Image appears slightly sharper (no surprise) and colour actually looks a bit better, to my eyes.

Imported both JPG and RAW file into LR, with profile set to Camera Neutral V2, then opened both in PS from LR.
The RAW file processed through LR is slightly but noticeably different from the RAW process into PS through ACR.
This was a surprise, given it should be the same engine.
The JPG imported through LR to PS looks identical (as far as I can tell) to the JPG loaded directly into PS.

End result, will probably just stick to importing through LR and opening in PS and not try to make any more comparisons.

Interesting.

I have just tried that and the RAW image opened in Ps from Lr was identical to the RAW image opened in Ps from ACR.

Are you sure that your Lightroom preferences and ACR preferences are the same?

I thought so but who knows ?

A few things reset during updates but it is worth checking, especially if I have different colour spaces selected.

I'll have another look and see if I can find differences.

Hi John,

OK, now I've lined up the preferences between LR and PS (they were different!).
RAW imported directly into PS now looks identical to that imported into LR then opened in PS.
Surprisingly there is a very slight difference between the corresponding JPG opened directly into PS to that opened from LR into PS.
The difference is trivial, not visible in the image but a very slight shift in the histogram.

Close enough for me.

many thanks