I 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 RepliesWhat is wrong with my GIMP? This behavior persists in every 2.6 and 2.8 build I've tried, in fact I'm pretty sure I first discovered it somewhere in 2.4 .
It's GTK bug #644032 - certain adjustments made to the Hue-Saturation tool (with overlap) may have problems handling the red/magenta wraparound properly. Which was supposed to be fixed eons ago (and with exception of this one specific usecase, it already WAS - see GTK #527085).
It originally happened while trying to adjust the color balance on a scanned image containing ambiguously red/magenta hues (yes I know we have an actual tool for Color Balance, but I've never been able to quite wrap my head around what adjustments yield which results). I have attached a sample file demonstrating expected vs. actual results with this usecase. My GIMP is clearly screwing the pooch on these adjustments ... but HOW, because even when I browse the online git repo the relevant source code looks like it should work perfectly (I've even mentally stepped through it and verified correct results, unlike my actual GIMP).
Try performing the same adjustments on your GIMP (note which build and version) - do you get the same results I do?
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?
I'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).
If I'm using the color mask and i want to know the luminosity of an image can I use it for Luminosity mask?the reason is PP does not have something as Photoshop.
View 12 Replies View RelatedI would like to know how the white balance is calculated on GIMP.
View 3 Replies View RelatedI have some jpg files with a wrong white balance.Flash refused by taking the picture.How can i correct this in GIMP?
View 4 Replies View RelatedI find that if I have some video that has poor color, if I grab a still from it and bring it into GIMP, GIMP does a good job on correcting it.
Now, I'd like to know what color correction settings were applied by that filter so that I can go back to my video editing package and apply similar color corrections across the entire video clip, not just the still.
Is there a way to adjust the colour balance on multiple layers at the same time?
View 2 Replies View RelatedThis is my first experience with GIMP.
I'm ready to start organizing my dad's pictures. As from now I have 1330 pic's scanned and I want to enhance them. I found out that a lot of pics need to have a new White Balance. To do this one by one will take me a year. So, the question is: How to manipulate this "auto white balance" for a lot of selected pictures?
I have noticed that using "Stretch Contrast" gives a much more contrasty image than using the "White Balance" option. Isn't it supposed to be the other way round based on the description?
I'm using the GIMP 2.8.0 for Windows.
Also "Stretch Contrast" is very close to "Normalize" and "Normalize" does seem to shift color in exactly the same way as the "Stretch Contrast" option, although based on the description, it shouldn't.
I want to make a script-fu with the White Balance auto correction(Colors->Auto->White Balance).I couldn't find any procedure/plug-in in the procedure browser that do that.
How to call this procedure? or, it there a way to do it manually?
I am trying to come up with a script for batch processing since i have 800 pictures that need editing.
(define (do-many dir) (let* ((files-list (car (cdr (file-glob dir 0)))) (do-one (lambda (f) (gimp-color-balance)))) (plug-in-color-enhance RUN-NONINTERACTIVE image drawable) (plug-in-unsharp-mask RUN-NONINTERACTIVE image drawable 5.0 0.5 0) (map do-one files-list)))
Now i tried this in the console but the script stops no matter what part i try to fix.
First, a slightly long winded explanation. Shooting the creative family Christmas card this year in a Mini-Cooper (original 60's one). Basically set my lighting up and then shot individual members in the car to post them together. The only snafu - my 20 month old son wasn't exactly cooperating, so the 'good' photograph I have of him is in the drivers seat, and I wanted to move him in between us.
There were a few difficulties here. First, the light changed between originally shooting my wife (windshield was clear), as skies were blue, and when I took the photo of myself nearly an hour later (cloudy skies cast a glare on the windshield. I had a black scrim set up to the side which worked, but wasn't able to knock it out all together. So i faded the clear windshield from my wife's side over to my side with the glare, but I feel that looks fairly natural (or at least good enough for the Christmas card).
The trick comes with my son - I cut him out from where he was at the drivers seat (had to do some shoddy work on his shirt where the steering wheel blocked him), and put him in between us. However, it looks like his coloring is off from what we are - and I can't quite seem to get it right. Color balance is definitely not my strong suit in PS.
I am using LR 4.4 on an iMac. Why the White Balance Selector tool would disappear when moved across an image?
it seems to change to a vertical line with an arror top and bottom.
The areas of the image on which it disappears seem to be consistent, in other words, it disappears on the same portion of the image eveytime.
UPDATE: Since posting the above a few minutes ago I've noticed that my cursor is behaving eractically. For example, on a different image to the one used above, in the library module using the Loupe the cursor changes from a magnifying glass to an arrow pointing to the right. It does this on the same part of the image every time.
how do i get the drop down box in white balance to allow me to change the white balance
View 1 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 RelatedI'm on Win 7, 64 bit, and CS6 (released). I've got the Spot Healing brush active and I Shift + Right-click to bring up the Blending options. I cannot change to Luminosity. It will change in the drop down box on the tool bar however.
When I first noticed, it was Lighten that it wouldn't change to. I've rebooted the PC a couple of times and now it seems to be the Luminosity mode.
How to create a luminosity mask in Photo paint?I know there was a macro but the site is in Russian and I'm not so good in that to read the instructions.
View 13 Replies View Related