Affinity Photo Apply image from green to gold by color LAB

[SCarini]

Hello, can anyone tell me how to get this?

See images "before" and "after"

Here is how it's done in Photoshop

• go from RGB to Color LAB
• Apply image 
• Layer: Background + Channel: B
• Blend mode: Overlay (or Soft Light)
• go from Color LAB to RGB

Thanks a lot

[kirkt]

@SCarini - Apply Image works a little differently in AP compared to PS.  For what you want to do, you will need to use Equations in the Apply Image interface.

1) The base image (the green image) we will call "Source" (S).  Duplicate the Source (CMD+J) and rename that duplicate "Destination" (D).

2) Set the blend mode of the Destination layer to Overlay.

3) Make the Destination layer the active layer (target it b clicking on it in the Layers panel).

4) Choose Filters > Apply Image... Here is where you will apply the b channel in the Source layer to the L, a and b channels of the Destination layer.  

4a) Drag the Source layer from the Layers panel onto the Apply Image dialog - this tells the Apply Image dialog that you want to use the Source layer as the SOURCE (S) for the operation.

4b) Check the box next to the Equations header toward the bottom of the Apply Image dialog - this tells the Apply Image operation that you will be performing operations on the Destination channels by using equations.  In Equation lingo, S denotes the source channel and D denotes the destination channel.  In the Equation Color Space dropdown menu, choose Lab.

4c) Input the following equations:

DL = Sb

Da = Sb

Db = Sb

DA = SA (the alpha channel does not matter here).

What this is telling the Apply Image operation to do is put the Source b channel into the Destination L channel (DL = Sb), put the Source b channel into the Destination a channel (Da = Sb) and put the Source b channel into the Destination b channel (which is the same thing).

4d) It appears that when you use Equations in the Apply Image dialog, the blend mode specified in the Apply Image dialog is not relevant.  Therefore, once you apply the Apply Image operation, the resulting layer will have to have its blend mode changed to Overlay - you already did this in Step 2 above, so the result you see after the Apply Image operation should be what you expected.  Repeat this exercise without changing the blend mode in Step 2 and see what I mean - the Apply Image result will look wildly different, but all you have to do is change the blend mode of the Destination layer to Overlay, and all is well.

Have fun!

If you ever want to perform an Apply Image operation where you want to change only one channel, just enter an equation for the other channels (the untouched channels) as:

D(channel) = D(channel)

That is, the Destination channel (the result) is equal to the Destination channel.

Kirk

[kirkt]

You will also probably notice that the result is slightly different in AP than in PS - I think AP handles Lab slightly differently than PS, so the colors are shifted slightly.

Kirk

[kirkt]

What is really convenient about AP is that your image does not need to be in Lab mode to do this - you can leave it in RGB mode and just specify Lab equations in the Apply Image dialog.  All of the computations and conversions are done on the fly without needing to convert back and forth from RGB to Lab back to RGB.

Kirk

[SCarini]

Thank you Kirk!

I soon noticed by your attachment that the result is different in AP than in PS

I will follow your instructions, then I will also try with Soft Light instead of Overlay

I will be back with my results.

[SCarini]

Here is Apply image + overlay 

[SCarini]

Here is Apply image + soft light

it does not change from green to gold as in PS 

[SCarini]

Here is Apply image + Pin light

it is half way between green and gold

[SCarini]

I found other interesting results with other blend modes

here is Apply image + hue

 

[SCarini]

Here is Apply image + saturation

 

[SCarini]

Here is Apply image + color