Combining Images

Moderator: jsachs

tomczak
Posts: 793
Joined: April 25th, 2009, 12:56 am
What is the make/model of your primary camera?: Fuji X-E2
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Re: Combining Images

Post by tomczak » January 13th, 2020, 4:01 am

Another analogy that helps me thinking about it - perhaps simpler than the slide projectors metaphor:

Go from the bottom up, in two steps:

Step 1: the Input image is blended with the Overlay image, with the Overlay Amount slider controlling the Overlay image content in the mix.

Step 2: the output of the Step 1 blend is blended again with the Input image, with the upper Amount slider controling the Step 1 blend content in the final Composite output image.
Maciej Tomczak
Phototramp.com

tomczak
Posts: 793
Joined: April 25th, 2009, 12:56 am
What is the make/model of your primary camera?: Fuji X-E2
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Re: Combining Images

Post by tomczak » January 13th, 2020, 4:48 am

To me, the logic of all this is that the Composite, just like most other transformations, does something to the Input image to create an Output. It this case it mixes the Input image the Overlay image according to the Operation method and the Overlay slider.

The Amount slider does what it always does in all other cases: it allows to water down the transformation output by blending its result with the virgin input to balance the final output.
Maciej Tomczak
Phototramp.com

Robert Schleif
Posts: 97
Joined: May 1st, 2009, 8:28 pm

Re: Combining Images

Post by Robert Schleif » January 14th, 2020, 12:57 pm

The recent addition of the equations to Help really helps me.

tomczak
Posts: 793
Joined: April 25th, 2009, 12:56 am
What is the make/model of your primary camera?: Fuji X-E2
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Re: Combining Images

Post by tomczak » January 14th, 2020, 1:50 pm

So if those Blend formulas are translated to Composite scenario with and extra Overlay Slider in between, would this be true?:

L Overlay amount value
O' Intermediate output after applying Overlay Amount Slider, but before applying the Amount Slider

O' = A * (1 - L) + R * L
O = A * (1 - X) + O' * X
Maciej Tomczak
Phototramp.com

jsachs
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Joined: January 22nd, 2009, 11:03 pm

Re: Combining Images

Post by jsachs » January 14th, 2020, 2:18 pm

Yes, the overlay amount is applied first and then the base amount.
Jonathan Sachs
Digital Light & Color

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