Changing colour to a defined value

[Stagecoach]

I have been asked if it would be possible to change the 'background' colour/shade of some images as the one below to a colour/shade within an organisations colour scheme.



An assumption had been made that the colours I used which some will remember were bluish, pinkish and yellowish were digitally produced but were simply reflection from coloured background papers.

I have the CMYK and RGB values of the organisations primary colour that they would prefer as the background.



I'm thinking along the lines of the possibility of being able to say in PS select all this shade and convert it to this but have not got a clue so any advice would be very much appreciated.

Grahame

[Shadowman]

You can use the adjust Color function under the Enhance menu to select adj hue/saturation, use the color picker to select that area and even try to zero in on the exact values you want to change. You just have to be careful that those tones aren't in the main subject but for this composition it'll probably only appear in a reflection. There's quite a few YouTube videos that'll walk you through the process.

[DanK]

In this case, it's beyond my skills. If the border between what you want to change and the rest is clear in terms of color, you can just select by color. However, I tried it with this image, and because of the fine hairs and the reflected color at the bottom, I couldn't get a clean selection.

[Manfred M]

Is this along the lines of what you are looking to do? This is my 5 minute effort.



The Photoshop Color Picker tool lets the user select by colours. That's the "easy" part, but unfortunately the contamination from the original background colour, especially with a transparent / translucent subject can be a real challenge.

Technique is to select the colours with that functionality and create a hue / saturation adjustment layer. Then play with the hue slider to create the right colour background. A soft, low opacity brush is used to reduce the contamination on the part of the image you want to keep. Selective desaturation might also be used on the subject to get rid of the pink colour cast.

Easiest way would be to photograph this on the correct coloured background, of course.

The tools themselves are a bit unsophisticated, so I would probably copy a patch from the Pantone colours to a new layer and use that as a visual reference as I played with the hue slider. I put a R=10, G=164, B = 208 colour patch on the work piece and eye-balled the colour.

In the latest version, I desaturated the mosquito and used the inverted mask I used in the edit and applied 15% opacity colour based on the Pantone numbers. I have added a curves adjustment layer and was able to match an area of the background to the Pantone colours you listed.

I placed a swatch that matched the Pantone colours and eyeballed it to get a close match. I then put on a curves adjustment layer and matched the colours exactly by dropping a colour sampler tool to get a reading as I adjusted the values in each of the individual colour channels.

[xpatUSA]

I have been asked if it would be possible to change the 'background' colour/shade of some images as the one below to a colour/shade within an organisations colour scheme.



An assumption had been made that the colours I used which some will remember were bluish, pinkish and yellowish were digitally produced but were simply reflection from coloured background papers.

I have the CMYK and RGB values of the organisations primary colour that they would prefer as the background.



I'm thinking along the lines of the possibility of being able to say in PS select all this shade and convert it to this but have not got a clue so any advice would be very much appreciated.

Grahame

One HSV adjustment in RawTherapee:



Exact color would need to be arrived at by trial and error ... note RGB is in %, not /255.

Don't know if PS has anything similar, but RT is free and can be quite rewarding for this kind of work.

[Manfred M]

One HSV adjustment in RawTherapee:



Exact color would need to be arrived at by trial and error ...

Don't know if PS has anything similar.

Looks like we got to the same place using different tools. I see that your version needs the same kind of colour contamination cleanup mine does in some of the finer areas of where the subject and replaced background meet.

[xpatUSA]

Looks like we got to the same place using different tools. I see that your version needs the same kind of colour contamination cleanup mine does in some of the finer areas of where the subject and replaced background meet.

Thanks, I was editing and missed your post. I actually left the image small while adjusting so didn't notice the contamination - in too much of a hurry to post, eh?

I use RT because I'm totally unfamiliar with the world of layers, brushes, masks, etc. I do have the GIMP but it's mostly double-dutch to me ...

[Stagecoach]

Thanks all for the replies.

I was familiar with the method of using the change hue/saturation procedure and then cleaning up the mosie but was looking for something more 'scientific' than trial and error.

Various attempts I undertook gave results similar to Manfred's example and in none of them I could achieve the low value in the Red channel as per their colour swatch.

[Manfred M]

Thanks all for the replies.

I was familiar with the method of using the change hue/saturation procedure and then cleaning up the mosie but was looking for something more 'scientific' than trial and error.

Various attempts I undertook gave results similar to Manfred's example and in none of them I could achieve the low value in the Red channel as per their colour swatch.

I used the curves adjustment layer and the Info Panel shows the results. The values on the left are the input ones and the ones on the right, that are the Pantone values you showed that the curves layer has adjusted for. The Color Sampler tool eliminates trial and error.

[Stagecoach]

I used the curves adjustment layer and the Info Panel shows the results. The values on the left are the input ones and the ones on the right, that are the Pantone values you showed that the curves layer has adjusted for. The Color Sampler tool eliminates trial and error.

There's something I'm missing here Manfred. When I use the colour checker on the image you have just posted it shows Red values of around 96 in the area you also selected.

[Manfred M]

There's something I'm missing here Manfred. When I use the colour checker on the image you have just posted it shows Red values of around 96 in the area you also selected.

That seems to be related to what the screen capture software does. When I load the screen capture I get values of 97, 160, 195. Yet when I load the image file I worked on I get the original image I get the same values that are shown. I pretty sure that the screen capture software is NOT colour managed.

The process works and would be best when applied to your original file. The manipulated image does not look the same as the original on my screen. The process in Photoshop works and is repeatable.

[Stagecoach]

That seems to be related to what the screen capture software does. When I load the screen capture I get values of 97, 160, 195. Yet when I load the image file I worked on I get the original image I get the same values that are shown. I pretty sure that the screen capture software is NOT colour managed.

The process works and would be best when applied to your original file. The manipulated image does not look the same as the original on my screen. The process in Photoshop works and is repeatable.

I am coming to the same conclusion regarding the 'screen capture' accuracy.

I'll do some more work with this later when I have time, but at present I'm having to supervise corrective work on my new slipery roof in between rain showers

[xpatUSA]

I am coming to the same conclusion regarding the 'screen capture' accuracy.

I'll do some more work with this later when I have time, but at present I'm having to supervise corrective work on my new slipery roof in between rain showers

In between the file color picker values and a screen picker app's values, there are color profiles and the screen driver. In my system those numbers are always different and I would be amazed if they were the same.

An extreme case would be me posting a JPEG with ProPhoto values + profile and what would be shown as screen values on your screen.

Noticed a similar effect long ago in Elements 6 - different picker values between 'converted' and 'assigned'.

Download this and compare file vs. screen values:

[Manfred M]

In between the file color picker values and a screen picker app's values, there are color profiles and the screen driver. In my system those numbers are always different and I would be amazed if they were the same.

An extreme case would be me posting a JPEG with ProPhoto values + profile and what would be shown as screen values on your screen.

Noticed a similar effect long ago in Elements 6 - different picker values between 'converted' and 'assigned'.

Download this and compare file vs. screen values:

All of the edits and postings I did were sRGB. No other colour space was involved.

Unfortunately, screen captures are the only way I can show what I did with the shot. I don't generally expect someone to use it as the basis for further editing. I post the actual edits on either Flickr or TinyPic.

[xpatUSA]

All of the edits and postings I did were sRGB. No other colour space was involved.

Unfortunately, screen captures are the only way I can show what I did with the shot. I don't generally expect someone to use it as the basis for further editing. I post the actual edits on either Flickr or TinyPic.

Hopefully, there is a simple misunderstanding; I wasn't addressing your color management - just trying to explain why screen values are often, if not always different than file values. Here's a file open in an editor; it's an sRGB JPEG with sRGB working space selected, sRGB profile ... and also shown is a screen color-picker:



Same pixel, different values, ipso facto.

[Stagecoach]

Manfred, Ted

Now that I'm not in so much of a rush dealing with such complicated issues as my theory that water runs along a guttering from high to low I'll recap on my post No 10

What I was intending to say was that as shown in Manfred's example of his colour picker readings 70/152/208 I had been unable using the hue/saturation adjustment method to achieve a Red value as low as 10 (as in the colour swatch figures).

I confused matters by bringing the difference between actual file and screen capture readings into things.

So, for now I will take further time in trying to achieve the desired 10/164/208 values in at least one area of the image.

[xpatUSA]

Manfred, Ted

Now that I'm not in so much of a rush dealing with such complicated issues as my theory that water runs along a guttering from high to low I'll recap on my post No 10

What I was intending to say was that as shown in Manfred's example of his colour picker readings 70/152/208 I had been unable using the hue/saturation adjustment method to achieve a Red value as low as 10 (as in the colour swatch figures).

I confused matters by bringing the difference between actual file and screen capture readings into things.

So, for now I will take further time in trying to achieve the desired 10/164/208 values in at least one area of the image.

Thanks for the clarification, Grahame. How picky is your client as to color accuracy ... ya know, the Delta-E color-difference thing?

As to "in none of them I could achieve the low value in the Red channel as per their colour swatch."

In an RGB triplet with a lower value such as that red, increasing the saturation (HSV/HSB) will lower the said red until, at 100% saturation, the red will go to zero. If the red is already at 0, the opposite applies: lowering the saturation will bring the red up until at the limit (saturation = zero%), the red will of course be equal to the other two.

HTH.

[Manfred M]

Hopefully, there is a simple misunderstanding; I wasn't addressing your color management - just trying to explain why screen values are often, if not always different than file values. Here's a file open in an editor; it's an sRGB JPEG with sRGB working space selected, sRGB profile ... and also shown is a screen color-picker:



Same pixel, different values, ipso facto.

Yes Ted, there was definitely a misunderstanding. I think I understand what you are saying

The screen is probably the weakest in the colour workflow, for the reasons you have pointed out (software, hardware, etc), other than perhaps the person staring at the screen. That being said, with Grahame and I using the same piece of software (Photoshop) on the same image file, the resultant values should be the same. I've spent a lot of time editing the same file on different computers and that has always been my experience. If he can't get the red value as low as I can, I suspect a difference in our workflows, rather than something else.