is there a way to view the RGB channels luminosity only? It seems I have to shut off two channels just to view one, and that one will be colored (red, green, or blue). How can I just view the channel in grayscale? Is this possible? Do I always have to shut two channels off to view one?
Also, I take it there are no adjustment layers in GIMP, correct?
Recently I noticed the histogram in PS4 displaying color channels instead of luminosity. And all three RGB colors seem to spike off the top of the window. Is there a way to only display the luminosity histogram curve? Also, how often would be considered normal to have to re-set preferences?
View 6 Replies View RelatedI have a picture taken by a nasty camera : one side of the image is more luminous than the other. I need this image to be analyzed by another software that count cells, so it is very sensitive to color differences. I would like to normalize the light over the entire picture, so that the soft will effectively count cells. Is there a function in GIMP that allows to do that ?
View 1 Replies View RelatedI've been putting together some tutorials for photographic retouching in GIMP, and have recently completed what I think might be useful to other GIMPers to know about: Luminosity Masks.
The basic premise is to use masks based on the luminosity of an image to restrict layer modifications to certain tonal values (only adjust light tones, or dark tones, or mid tones for instance).
Many people point to the Luminosity Masks tutorial by Tony Kuyper, so I put this together to show the same workflow for GIMP (there's also a short tutorial on using the masks for doing split toning in images).
I am trying to convert an image that I took in SlideBook using fluorescent dyes to label proteins on a cell. The original image has two channels (red and green) with different intensities for each which correspond with the amount of each respective protein present. The problem is when I open the image in PS and convert it to RGB mode, all three of the channels have the same intensities so I get a black image. If i vary the contrast I can see the image but it is in black and white and the intensities of each channel are the same so I am unable to separate the two colors. I need to be able to see both channels (red and green) with their original intensities but I cannot figure out how!
View 3 Replies View RelatedI was wondering if there was an easy way to view individual color channels (Red, Green, Blue) in the viewer, and if so what the shortcuts are. I know you can do this simply in flame but can't seem to find a way to do it in Smoke.
View 3 Replies View RelatedI need to move one color channel from one image to anther and completely replace the channel.
View 3 Replies View RelatedSome .BMP files.
I need to save some images with transparency that are in .BMP format, but said images seem to have what's called an alpha channel, which covers all of the image's background and not the transparency that I need. I've tried to use the "Convert color to alpha" option, but it appears that that only works in the image that I want and not in the alpha channel itself (yeah, I didn´t know what alpha channel was until then).
I leave an example of one of the various .BMP files that I want converted to .PNG with transparency.
Is there anything that can be done using an alpha channel, that can'tbe done using masks and layers, or vice versa? Context of question: I've worked extensively with masks and layers.I've never worked with alpha channels.For example:
Using an alpha channel:
1. Open two single layer images, A and B, neither one of which has analpha channel.
2. Drag the image B over to A and close B.3. Now image A has two layers, A and B. Put layer A on top, selectlayer A, set the blend mode to Normal, and add an alpha channel.4. Erase part of layer A, where-ever you want layer B to show through.At this point, layer A has an alpha channel with white where you wantlayer A to show, and black where you want layer B to show, but it doesnot have a mask.
OR
Using a layer mask:
1. Open two single layer images, A and B, neither one of which has analpha channel.
2. Drag image B over to A and close B.3. Now image A has two layers, A and B. Put layer A on top, selectlayer A, and set the blend mode to Normal (don't add an alphachannel).
4. Create a solid white mask for layer A. Paint black on the maskwhere you want layer B to show through.At this point, layer A has a mask with white where you want layer A toshow, and black where you want layer B to show., but it does not havean alpha channel.
In both cases, using a mask or using an alpha channel, the net resultis the same.So again, is there anything that can be done using an alpha channel,that can't be done using masks and layers, or vice versa?
I cannot bring up Layers, Channels, or Paths. Running Gimp 2.6.10 on a Windows 7 machine. Selecting Windows...Dockable Dialogs...Layers or Channels or Paths does not bring up a new dialog window. Also there is nothing in Windows...Recently Closed Docs
This occurs regardless of image file opened. Not sure how long this has been the situation as I have not been using gimp on the computer where this problem is occurring for a couple months. Am not an advanced user though have used it occasionally for years. All other Selecting Windows...Dockable Dialogs... actions bring up window boxes normally. Tab does toggle display for the Toolbox etc. Just Layers, Channels, or Paths have an issue and I suspect it may have occurred because they were sharing the same window box. I did reset Preferences.
I am able to readily create layers on top of a base image but without the dialog box, only have access to the last one created. Also can merge down the last new layer or flatten the image. My suspicion is gimp may be displaying the dialog box at XY coordinates beyond my monitor screen displayable coordinates. There is a configuration file that saves the last used settings that I can simply delete?
How do you get the 'Layers, Chanells and Paths' tool bar to appear. I am running Xubuntu 12.04, Gimp 2.6.12 and it does not appear. Can not upgrade to 2.8 because Ubuntu Software Center does not have it. I need this sub-window to wotk with test-along path.
View 3 Replies View RelatedI have three different pictures in separate files, and I want to overlay them as red, green and blue channels in a new file. (the images represent the different color channels obtained from fluorescence microscopy, and I just want them back in one picture).
I guess it´s pretty easy, but I don´t manage to get all 3 pictures into 1 as 3 separate channels.
Basically, I am trying to use an alpha layer/channel to export a picture that is transparent except for a grass clump that is colored green over the alpha layer. So the picture looks like a solid green rectangle, but is actually a green blade of grass.
Problem is, I cannot get the alpha layer to work. I can't follow the tutorial as it is in photoshop, and random videos on-line haven't worked.
(Here is the tutorial: [URL]...... from 08:40 - 09:30)
(I have also attached my practice file as a TGA)
Is there a preference in GIMP to display color channels in grayscale? Rather I should ask, has this issue been resolved because I know at one time it was a big difference between PS and the GIMP. And yes, I know that I can decompose and recompose...
View 5 Replies View RelatedHow do I quickly separate an image's channels into grayscale layers? I'll need to do this frequently, so is there an automated way? If there isn't, can it be done with python scripting? Would it take me a long time to learn how to write such a script assuming I know a bit of Python (as used in Blender), but haven't done any scripting with GIMP?
View 2 Replies View RelatedThe Layers, Channels, Paths Dialog Window doesn't appear on my screen. Have tried everything I can think of.
View 2 Replies View RelatedThe Layers, Channels, Paths Dialog Window doesn't appear on my screen.
View 1 Replies View RelatedWhat are they used for? I have been using PS for around 3 years primarly for web design and I have never used channels outside of loading a selection. I searched for more info; I mostly got tutorials that use alpha channels, but no real explanation as to what they primarly do.
View 9 Replies View RelatedWe all know the invert function of Photoshop, easy and nice (well nor always but will fix this) to invert all colors.... The downside is than this trick will also invert luminosity... Light area become dark and dark area become light, this can ruin an image!
If you wish to invert an image and keep lighting intact the trick is really simple!
1) Open an image to be inverted
2) Duplicate you background layer (or the image layer), this layer will be used as a luminosity mask.
3) Select your original layer
4) Invert you original layer
5 (Optional) Link and Merge these layers
Done!
Trick : If you invert the luminosity(the copy of the original) rather the than original layer, you will inver the lighting of the image... Its also pretty cool!
I have always used the shortcut Ctrl+Alt+~ to get luminosity selection. It always worked in Photoshop CS3 and still does on my computer, but when I try it in CS4 nothing happens and it doesn't work. Do I have a preference or setting wrong?
View 6 Replies View Related1. Duplicate the image which is in RGB mode
2. Change the mode of the duplicated image to LAB color mode
3. Select "lightness" channel in the duplicated image
4. Move it into the RGB image as alpha channel
5. Copy this channel and invert the copied channel
6. Create two HSL adjustments with these two channels used as masks
7. Turn off completely the saturation sliders in the HSL adjustments for desaturating the image
Now, I can not get completely desaturated image after these steps..Is there a leakage between my luminosity masks?
I'm trying to get a better understanding of luminosity masks. Where can I find out just what operations Photoshop is performing when I control click on the rgb composite channel to make a selection (which I then save as an alpha channel)?
My assumption is that the brightest half of the image pixels are included in the selection and the rest are consigned to black. Is that even in the ballpark?
I am trying to calibrate my screen using gretagmacbeth eye one. Everything works o.k. apart from my colour temprature and luminosoity. The colour temprature is way down approx 10% and so is the luminosit, it is no where near the rcommnded levels. To the extents I have now got a red tint on my screen due to the colour temprature.
So how can i overcome this, can i buy a special lightbulb or kit for the room i work? Or what do I do?
Hican i do a color luminosity mask ?for example for a range of colors or for yellow? may somebody help me?
View 11 Replies View RelatedIn the histogram palette menu there are red, green and blue histograms to give the saturation of those colors, and a luminosity histogram to give the overall ( greyscale) brightness. There is also an RGB option, presumably to give a composite version of the red, green and blue saturation.
In Levels, however we have the same thing, except there is no luminosity option, only RGB. But RGB in this case cannot be a composite of the three color channels, as we use it to adjust brightness and contrast; in other words it is presumably the same as Luminosity in the histogram palette. Despite this, when I do adjustments to an image the RGB histogram in Levels looks identical to the RGB histogram in the histogram palette. I'm using PS 3 Extended.
Colorizing a photo can be fairly simple using Adjustment layers and Hue/Saturation, what I've never been able to do though, was convert black to white within a photo. The other way around, white to black, is fairly easy to pull with decent and satisfactory results. Black to white on the other hand, seems to give a lot of trouble in maintaining proper and believable luminosity. If I have a black plastic object, for example, that I'm attempting to turn white... through all random experimentation I have done the object either becomes another 'material'... ie. metallic, or the object becomes too washed out (loses detail) to even make the eye believe the change is real and the material is still the original. I do know, though, that people are capable of creating the illusion of all sorts of material and surface through photoshop. So, if someone has an idea on how to 'colorize' and image while maintaining the original and proper reflection of light on the surface of the object,
Attempting to lighten plastic center plate using levels, loses correct material luminosity and becomes metallic
Attempting to lighten plastic center plate, using Lightness/Saturation, loses vast amount of surface detail, becomes 'flat' and washed out
I'm trying to replace a colour in PE9 (Enhance > Adjust Color > Replace Color) but it's only replacing the luminosity, not the colour.
For example, I'm trying to replace a pasty white with full red (255,0,0) and it just comes out grey....
I can't find any switches for 'color/luminosity/hue' etc
New action set?
View 1 Replies View RelatedI'm currently recording the median luminosity and standard deviation of luminosity values in various photographs. This has been an ongoing project so I've been working on it for probably the last 4 months. Today I resumed my work and had to go back and check a previous photo that I had already recorded luminosity values for and noticed that the luminosity values that I had originally recorded were different than the values I'm seeing today in the histogram.
The attached picture shows the histogram I'm using (and have been using since I started this project). It is showing a median luminosity and standard deviation of luminosity for a photo that originally gave me this median luminosity value: 75 and this standard deviation: 27.87
I accidentally changed some setting in photoshop that affected the luminosity readings, or if the luminosity values of a photo are estimated by photoshop and thus aren't always the same etc. ?
Is there a way to assign this to a shortcut key?
View 8 Replies View RelatedI know what the documentation says that they do, but it doesn't appear to be the truth. For example, if I take my image and overlay it with a 50% gray layer set to Luminosity mode, I would expect to see the hue and saturation of my image, with the luminosity of every pixel set to 50%, but that isn't what actually happens.
View 12 Replies View Related
