Questions tagged [channel]

Questions about using separations of colors in digital images.

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Gimp: How can I control blur strength via data from a channel?

I want to apply a blur, but for the blur distance (strength) to depend on the corresponding value of a given channel. For example, if my control channel has a gradient from black at the top to white ...
tremby's user avatar
  • 101
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2 answers

Saving spot color channel file as a TIFF in Photoshop

Is there a way to save a photoshop file as a TIFF with multiple spot channels in CMYK mode?
user161820's user avatar
2 votes
2 answers

Difference between "Empty area" and "Transparency channel" and "Alpha channel"

New to photo editing, so I've got some conceptional confusion about the colors and channels, In photoshop, we can create text layer, we can have text on top of an "empty space" the checker ...
Dew's user avatar
  • 123
0 votes
1 answer

Photoshop way of transferring layer's alpha "channel"

New Photoshop user trying it for the first time. I'm trying to get an inverted alpha "channel" but I can't. There are things I'm missing. Steps I took: Create sRGB 512 * 512 pixel document. ...
mireazma's user avatar
  • 103
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1 answer

How do I create this CMYK effect in Photoshop?

I assume there’s some channel separation but I can’t get an image that’s the same result.
rav's user avatar
  • 15
-1 votes
1 answer

Need help getting this color effect look [duplicate]

I've been trying to get a similar look as the photos in this image with the different color effects. I've tried messing with different blending options and even tried different gradient maps. However, ...
Brian Love's user avatar
1 vote
1 answer

How to create dropshadow on layer with alpha transparency in GIMP?

I'm working on a project consisting of a background image with several layers on top of it. Each of the layers consists of an image with alpha transparency, such that only part of each layer is ...
Bolio's user avatar
  • 185
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1 answer

GIMP: Why does "Channel to Selection" give such bright values?

As shown below, an extracted channel (here blue) gives a brighter result when using the "Channel to Selection" from the context menu in the Channels panel and creating a mask from that ...
ChameleonScales's user avatar
1 vote
1 answer

Move color channels and spot colour channel at the same time?

when I select part of my image layer and move it with the move tool, the colour channels move as expected but the graphic on the spot color channel stays where it is. I have to go back and select the ...
JKCapeTown's user avatar
1 vote
2 answers

How can I map a grey scale image to a specific color channel gimp?

I have a grey scale image, and I would like to map it to a specific color channel (red in may case), in gimp. That is, I would like to produce an image with only red channel, and that the red and non-...
Tav's user avatar
  • 13
0 votes
1 answer

GIMP not exporting personal channel

I have created an image with a parchment-like effect. I achieved that creating a personal channel and applying to it the filter Render > Noise > Solid noise. I then painted on different layers ...
Ntakwetet's user avatar
  • 151
1 vote
3 answers

Inverted colour-erase in GIMP (or extract specifc hue)

I have the below image that I would like to remove the background from. As well as some text grinning through from the back of the page, there are some vestiges of the paper colour (yellowish) and ...
Inductiveload's user avatar
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1 answer

How to invert the values of a specific color channel in Photoshop?

I want to invert the green channel for my normal map texture (for use in a program which uses different handedness from the program that generated it). How do I do that using Photoshop preferably (or ...
KeyC0de's user avatar
  • 125
1 vote
1 answer

How do I change specific channels with the curves tool in GIMP?

When I click the "Channel" dropdown in the Curves tool in GIMP, all of the channels are grayed out and I can only select "Value". What would cause them to be grayed out? What do I need to do to change ...
Aaron Franke's user avatar
1 vote
1 answer

How to merge 3 images into a single one by RGB channels?

I have 3 different images: for the first one I'm only interested in the RED channel; for the second one the GREEN channel; for the third one the BLUE channel. My goal is to create a single RGB image ...
user840718's user avatar
2 votes
2 answers

Gimp Python-Fu how to copy a channel

Suppose I want to copy the red channel of an image (thus creating a new channel). How do I do that with Python-Fu? EDIT: basically, I need to create luminosity masks. So far, I tryed the following ...
Davide_sd's user avatar
  • 145
1 vote
1 answer

How can I compare alpha channels pixel by pixel?

I've got two TIFF files with RGB and multiple alpha channels. The RGB channels are pixel by pixel identical. The alpha channels have values from 0 to 255. How can I compare an alpha channel in each ...
empty's user avatar
  • 153
2 votes
2 answers

Duotone psd file for (offset) printing

I read that answers at this question: Preparing design for duotone printing? I need it to be more specific about the step: use the complementary RGB channel, in this case Red (E) Play with the ...
Christos's user avatar
3 votes
1 answer

In a CMYK raster image, why does pure black look darker if I switch off other 3 channels?

File mode: CMYK CMYK working profile: Fogra 39 Grayscale working profile: Dot gain 15% Any region with pure black (0 0 0 100), if I turn off the cyan, magenta and yellow channels, it gets slightly ...
LWTBP's user avatar
  • 370