How to change gray background to white

[Nathan Tu]

I have picture has different gray background, need to change it to white, picture attached.

In Photoshop, I can select by color range, and then add sample, it will help me easily select all the gray color I want, then adjust it.

 

But in AP, I can't use the same solution, except using the selection brush tool.

Anyone knows a better and quicker way, cause I really don't want to select the gray area by using the selection brush tool?

[v_kyr]

In AP there should be similar selection capabilities, like "Selection -> Mark selected color..." and then adjust the wished tolerance settings for the selection. Further there are also tonal selections like "Select lights", "Select shadows", "Select intermediate tones", which then can be enhanced and if needed inverted etc. - Just give it a try.

[Nathan Tu]

4 hours ago, v_kyr said:

In AP there should be similar selection capabilities, like "Selection -> Mark selected color..." and then adjust the wished tolerance settings for the selection. Further there are also tonal selections like "Select lights", "Select shadows", "Select intermediate tones", which then can be enhanced and if needed inverted etc. - Just give it a try.

Thank you, but I think it's just not as handy as PS can do, anyway, this kinda solves the problems for now.

[Alfred]

Select the label, invert the selection, and then use ‘Erase White Paper’ to remove the off-white background; the wires have some highlights and are cloudy at the ends, so you may need to adjust the blend ranges to restore any opacity lost by the erasure. Add a white fill layer and move it below the image.

[HVDB Photography]

Selective Color Adjustment  

set Blues   > Cyan -100% , Black -100%

set Whites > Black -100%

 

Brightness/ Contrast Adjustment

set Contrast 60%

 

 

SelectiveColorAdj.afphoto

[R C-R]

24 minutes ago, HVDB Fotografie said:

Selective Color Adjustment  

set Blues   > Cyan -100% , Black -100%

set Whites > Black -100%

How did you determine that the Blues needed a -100% Cyan adjustment? This method worked quite well on this image but I would like to know how to apply it to others that might have a different grey background.

 

In this image, this does shift the greys of the label to white, but that is easily fixed by painting with black on the masks of the adjustment layers.

 

Very cool technique!

[HVDB Photography]

2 hours ago, R C-R said:

How did you determine that the Blues needed a -100% Cyan adjustment?

 

That is thanks to my trained eye for color cast detection.
As an amateur photographer, I notice a slight blue color cast with this image (on my calibrated screen).
One can check this by pulling the slide bar +/- 10% to the right via "White Balance Adjustment".
With the "Brightness/Contrast Adjustment" on top this produces a similar result but with a slightly warmer color tint. Matter of taste of course.

 

2 hours ago, R C-R said:

This method worked quite well on this image but I would like to know how to apply it to others that might have a different grey background.

 

That is depending on the image itself.
It's often trial and error. And it doesn't help all the time.
Sometimes using the "Channel Mixer Adjustment" can also be effective because there one can choose between:
Grey, RGB, CMYK and LAB colour format.
I did the test for this image using cyan under CMYK. 
Originally cyan was standing at 100%. If you pull the slider to 0% this also produces a similar result.
See the new "SelectiveColorAdj_[2].afphoto" attachment.

 

2 hours ago, R C-R said:

In this image, this does shift the greys of the label to white, but that is easily fixed by painting with black on the masks of the adjustment layers

 

Yes, but is slightly more labor-intensive.

 

SelectiveColorAdj_[2].afphoto

[Nathan Tu]

Really amazing, thanks so much, also really great for all the explanations.

[toltec]

You could also do it with a Curves Adjustment layer. Use the picker to select the grey and drag up (or drag on the curve), that's a bit like a selective adjustment. Move the darker areas to make an S curve (as shown in cyan).

 

 

After the main curve (Master), I moved the Red a little to remove the slight Cyan cast in the highlights.

 

[Nathan Tu]

1 hour ago, toltec said:

You could also do it with a Curves Adjustment layer. Use the picker to select the grey and drag up (or drag on the curve), that's a bit like a selective adjustment. Move the darker areas to make an S curve (as shown in cyan).

 

 

After the main curve (Master), I moved the Red a little to remove the slight Cyan cast in the highlights.

 

this method is also great and fast.