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Gimp decompose

Gimp decompose

In the interests of those of you who use Gimp, this blog post is a revisit on the topic of dragging color out of lackluster images this time using Gimp. One of the hidden secrets of Gimp is that it supports the LAB color space so you can get access to the L, a and b channels in an image.

Start out with an image that could use a color boost.

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Right click the Background layer and choose Duplicate Layer. Select this new top layer. From the color model dropdown list, select LAB.

You will want to decompose to layers so select Decompose To Layers and click Ok. Disable visibility on the L layer and click the A layer to select it.

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You should have a dark murky almost negative looking image on this layer. You can read off the values so pairs of values like 30,0 andor 64,0 andare good.

You need to make sure the line goes through the middle of the grid, or you will get an unwanted color cast in the final image. Click Ok.

Repeat this by disabling the visibility on the A channel and do the same on the B channel.

GIMP/Decompose

You should see no difference in the image at this stage. If desired, you can adjust the contrast in the L channel using curves — this will give you some additional boost in contrast in the final image. The L channel is the luminosity channel and it has no color in it at all so you can create a different shape curve here and there is no requirement for the line to go through the middle of the grid.

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The layers will be recomposed back into the original image. To see it, you will need to close the LAB version and return to your original image.Horrible things! But how to remove the cyan to produce the image on the right? Then I just made the cyan layer invisible to get the version of the test page on the right. No doubt there is a better way, but this is what I found. The result of all this is an image that looks exactly the same as the one you started with, but which is made of individual ink-gun layers that you can turn on and off.

All I did to produce the right-hand side of the image above was to make my cyan layer invisible. When toner is low, the printer just refuses to print. Is it possible to put the toner in wrong i. Whatever gets the toner out of the cartridge could be bad, the drum, the drum motor, or the thing wire?

But of course with this technique you need to compose each time you want to change which layers are displayed, rather than simply toggling a layer display. I mean, how obvious can you get, geezgosh?

Scheme is an interest of yours. My guess is planned obsolescence. Why would it suddenly have changed? Erza Bradford, thanks for the simpler workflow for just dumping the cyan component. I knew there had to be a way! Brian, writing this up as a Scheme script is a neat idea.

Although I am kind of tempted to take the easy way out and use Python Robert, your interpretation is cynical, jaded, depressing, pessimistic, and I fear probably right. I bought the printer on 17 Decemberso less then three years ago. This seems absurd to me — I am by no means a heavy user of the printer. I hate to say it, but the most cost-effective way of printing is probably to buy brand new low-cost inkjets, toss them out when the toner runs out and buy rolling replacements.

Anyway, my Dell cn has been working pretty well for a number of years with the same consumables. I really doubt that your driver is making it do that.

gimp decompose

Or; c The laser for that cartridge has died and nothing is being imaged on the cyan drum. Usually, though, HP printers are pretty good about detecting and reporting these kinds of internal problems. The only real fix you could hope to do yourself is to install a new cyan cartridge. Will this work for designing something in Gimp to send to a printer that needs the image to be in CMYK color??

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So i finally found this post, and it saved the day.Following options are described with Decompose to layers checked. This function is interesting when using Threshold tool.

GIMP/Decompose

You can also perform operations like cutting, pasting or moving selections in a single RBG channel. If the RGBA radio button is clicked, a image is created similar at the RGB Decomposing with a additional Alpha layer filled with the transparencies values of the source image. Full transparent pixels are black and the full opaque pixels are white.

This option decomposes image into three greyscaled layers, one for Hue, one for Saturation and another for Value. Although Hue is greyscaled, it does represent hues. In color circle, white and black are starting and arrival points and are superimposed.

They represent Red color at top of circle. Grey intermediate levels are corresponding to intermediate hues on circle: dark grey to orange, mid grey to green and light grey to magenta. Saturation and Value : White is maximum Saturation pure color and maximum Value very bright. Black is minimum Saturation white and minimum Value black.

This option is similar to HSV. Instead of the V alue, the third layer contains the image's L component. This option decomposes image into three greyscaled layers, one for Yellow, one for Magenta and another for Cyan.

This option might be useful to transfer image into printing software with CMY capabilities. This option might be useful to transfer image into printing software with CMYK capabilities.

This option extracts the image transparency stored in the Alpha channel in Channel dialog in a separate image. The full transparent pixels are Black the full opaque pixels are white.

The graytones are smooth transitions of the transparency in the source image. A channel is used for the Luminosity while two other channels are used for the Colors. The LAB color model is used by Photoshop. Each option decomposes image in three greyscaled layers, a layer for Luminance and two other for blueness and redness. It's based on the idea that the human eye is most sensitive to luminosity, next to colors. If this option is checked, a new grey-scaled image is created, with each layer representing one of the channels of the selected mode.

If this option is not checked, every channel is represented with a specific image automatically and clearly named in the name bar. This option is for specialists. It is related to CMYK printing. This allows you to make crop marks visible on all channels, providing a useful reference for alignment. A thin cross printed in registration black can also be used to check whether the printing plates are lined up.

Decompose 8. Decomposition to images RGB Original image. Decomposition to layers RGB Original image. Activate the command. Extract Channels Following options are described with Decompose to layers checked. Alpha This option extracts the image transparency stored in the Alpha channel in Channel dialog in a separate image.

Decompose to Layers If this option is checked, a new grey-scaled image is created, with each layer representing one of the channels of the selected mode. Crop marks Source image. Cyan component.Text and images Copyright C Eric R. Applying an unsharp mask to an entire image is not always appropriate.

Giving credit where credit is due: I did not come up with this method. You may want to maximize your browser window to properly see this tutorial. It is noticeably soft, probably due to bad autofocus.

Note: be sure to do any other editing that you want to on the image first, especially downsampling or upsampling resizing. It might be wise to minimize the original image window now.

gimp decompose

Go to the duplicate image. In the Edge Detect dialog box, select a parameter value of the appropriate size for the edges in your image. You may need to experiment with this. Note: in some tutorials they recommend converting to greyscale and then running the edge detection filter. My thinking is that there may be an edge in color, but not tonality e. Once you have converted to greyscale you may not be able to detect that edge any more. Bring the black point up and the white point down to filter out any insignificant edges.

You may need to play around with the exact positions of the sliders. A radius of between 3 and 10 pixels horizontal and vertical should be enough. If you want to you can use Levels again to adjust the white and black points of the mask. Open the Layers dialog. Click on the new channel button at the bottom of the dialog to create a new channel.

In the Layers dialog, make sure the Sharpening Mask channel is selected. Click on the Channels tab in the Layers dialog. You should see a tiny version of the sharpening mask in the channel icon, indicating that you properly pasted the sharpening mask into the new channel.

Important: in the Layers dialog, click on the Layers tab and make sure the luminosity layer if HSVBackground layer of Value window is selected, and is the only one selected.Lillqvist tml in and was supported in the GIMP 1. Following the first release, GIMP was quickly adopted and a community of contributors formed.

The community began developing tutorials, artwork and shared better work-flows and techniques. GIMP 0. It supported 8, 15, 16 and bit color depthsdithering for 8-bit displays and could view images as RGB colorgrayscale or indexed color.

At this early stage of development GIMP could select regions using rectangle, ellipse, free, fuzzy, bezier, and intelligent selection tools, and rotate, scale, shear and flip images. It had bucket, brush and airbrush painting tools, and could clone, convolve, and blend images. It had text tools, effects filters such as blur and edge detectand channel and color operations such as add, composite, decompose.

The plugin system allowed for addition of new file formats and new effect filters. It supported multiple undo and redo operations. It ran on Linux 1. Currently, user questions are directed to the gimpnet IRC channel. Improvements had been made to the painting tools, airbrush, channel operations, palettes, blend tool modes, image panning and transformation tools. The editing work flow was improved by enabling rulers, cutting and pasting between all image types, cloning between all image types and ongoing development of a layers dialog.

New tools included new brushes and a new brush file formatgrayscale and RGB transparency,"Bucket fill" patterns and a pattern selection dialog, integrated paint modes, border, feather and color selectors, a pencil and eraser paint tool, gamma adjustments and a limited layer move tool. At the time it was considered a code fork. It would later be merged into the main development tree.

Support was, and continues to be, offered through a yahoogroups email list. The biggest change in the GIMP 0. The pace of development slowed when Spencer Kimball and Peter Mattis found employment.

GIMP 1. An official website was constructed for GIMP during the 1. Marc Lehmann [37] developed a perl programming plug-in.

gimp decompose

The GIMP 1. No official release occurred during this series.Log in or Sign up. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More. Download Now Overview Version History Discussion. This plugin losslessly decomposes a layer of an image into layers of wavelet scales. This means that you can edit the image on different detail scales frequencies. The trivial recomposition of the image can be done by GIMP's layer modes so you can see the results of your modifications instantly.

Among the applications are retouching, noise reduction, and enhancing global contrast. Wavelet scales An image can be transformed into a set of wavelet scales. There are detail scales and one residual. The detail scales contain the image details of a their scale size. This means that scale 1 contains only image details of the smallest scale. Scale 2 details are larger and scale 3 details even larger and so on. This image illustrates this: This plugin computes these scales losslessly and creates a new layer for each one.

The recomposition is the addition of all scales which is done by GIMP using the grain merge layer mode. You can then paint the scales with your favourite tool, usingas neutral colour for the details, not the residual.

Values below neutral darken, values above lighten. The most straightforward thing to do is to use the paintbrush tool with the neutral colour and use different brushes and opacities. That way you erase details. Skin retouching The problem with skin retouching is retaining skin detail but erasing spots and such.

However, one might want to keep freckles in the face see image below. Achieving this is very difficult when operating in the normal image space.

The skin details such as pores and hair are very small, spots and pimples are larger. If you erase the larger spots with an airbrush for example you hide the skin details inside it. With wavelets you decompose the image into scales of different detail size. To state it simply: One scale will contain the skin details like pores, other scales contain spots.

They are rather nicely separated. Look at the image with the wavelet scales above.Text and images Copyright C Eric R. Jeschke and may not be used without permission of the author. Here is an example image, loaded into GIMP. I suspect GIMP uses a similar formula.

Here is what I get if I use desaturate instead. The result is visually different; note the increased contrast in the scales. You can see a lot more noise in the desaturated zoomed view examine the blurred area below the spikes.

Each one can be represented as an independent grayscale image. Here you can see the three channels: red topgreen middle and blue bottom.

You can see that the red channel contains most of the luminance information as well as a lot of noise, the green channel has the least noise, and the blue channel has shadows and noise. Yet another decompose option: LAB mode. The Lightness component is a very interesting one because it contains all of the luninance information whereas in RGB and HSV some of that information is spread into other components. The final technique is the Channel Mixer filter. Click the checkbox that says Monochrome.

Now play around with the levels of the three channels, seeing the results in the preview window. When you have something that looks decent in the preview, click OK. The advantage of the channel mixer is obviously flexibility. I like to decompose and examine the individual RGB channels, as we did earlier. That way I can see what is good and bad about each, and then use the channel mixer to combine them accordingly.

I liked the blue channel for the great contrast it adds to the scales.

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I was curious myself, and asked the author of the Channel Mixer, Martin Guldahl, about it. So the pixel values would be about Left image : The original image. The original tutorial used to appear on gimpguru.