Gamma Correction

I have a large number of family photos which I have scanned and stored as TIFF files. Now that I come to print them, I have found that the gamma needs correcting on all of them to make the prints come out right on the printer I have (Canon MG6300). Is there any software, Adobe or any other, suitable for this job?

No, gamma correction can't be done simply by adjusting brightness and contrast. I have videos that are too dark, and increasing the brightness only changes them from murky black to murky gray. But when I saved a still frame and looked at the image with the Mac's "Preview" application, whose Image Correction tool includes a "gamma" adjustment, I found that I could expand the range of black shades to approximate a decent-looking picture. Try it yourself and you'll see what "gamma" does.
MPEG Streamclip is a good program, though. I've used it to fix videos with faded color or poor contrast.

Similar Messages

Why Levels mid-point slider and Exposure Gamma Correction slider not the same?

Both the mid-point slider in Levels and the Gamma Correction slider in Exposure adjustment appear to modify Gamma. They even use the same numeric scale.
When Gamma <= 1, both sliders appear to produce the same results (confirmed with a couple of random sample settings and using the Difference blend mode).
When Gamma > 1, however, the results are very different. Levels produces more what one would expect in terms of moving the Gamma curve without moving the white and black points but the Exposure Gamma Correction slider seems to do something very different, either moving the black point or applying a very different curve the produces much brighter tones in the dark shadows.
Can anyone explain why and how these two adjustments produce different results?
Is this a bug with the Exposure adjustment?
By the way, in my limited tests of this I was just using a standard RGB file in 16-bit mode - nothing fancy like 32-bit or LAB or anything like that. Also, Photoshop CS6 Extended. Both 32- and 64-bit versions show the same behavior.
Thanks.

The differing gamma adjustment results also occur in the OS X version of Ps 13.0.1
The situation is worse than you realize, Dennis. Test with a linear grayscale gradient in 16-bit or 8-bit RGB mode instead of arbitrary images. Remember to view at 100% zoom for an accurate display.
Gamma adjustments of less than 1 performed by Levels adjustment layer and Exposure adjustment layer do differ but to a less obvious extent than when the adjustment is greater than 1. Differences can be seen in histograms, and low level differences when differencing layers can be made more obvious by adding an Exposure adjustment layer with the exposure increased.
You'll get further different results by using the gamma adjustment in the "Exposure and Gamma" method of Image > Adjustment > HDR Toning. Notice that the gamma value there has to be specified as the inverse of that in Levels and Exposure.
I haven't bothered to calculate which, if any, of the three gamma adjustment controls gives correct results because that is Adobe's responsibility.
It's quite ridiculous that a common routine giving consistent and correct results isn't being used for all these gamma adjustments. Code re-use makes software more robust, simpler to test, simpler to correct, leaner and overall easier to manage. But what do I know.

Gamma Correction - always necessary (?)

Has anyone else had a problem with their gamma curves being seemingly whacked after going through Compressor for DVD? I've been dealing with this for the last three years and haven't seemed to find anyone else on the web with the issues I've got. Maybe I'm seeing things.
I've been working with Varicam and XDCAM HD footage primarily. I've found that every time I export to m2v without any Gamma Correction filter adjustments, the video looks more milky and faded when viewed in the DVD Player application (after going through DVDSP) compared to the way it looks in FCP. But the m2v file looks fine when playing it though QuickTime Player. When I apply a Gamma Correction filter in Compressor to compensate for this milkiness, I get a great picture in DVD Player, but in QuickTime, it looks a little dark.
Am I compensating for something I don't need to be compensating for? The reason I feel like I need to be compensating is because when I play regular store-bought movies on DVD Player, they don't have the same milky look in their blacks as I see in my exported files. And I know I'm not supplying milky footage because my deepest blacks are at or very near 0 IRE, and it looks great in FCP and QuickTime.
Anyone know what's going on? I've had this problem through all generations of FCP/Compressor/DVDSP that I've worked with for the last three years or so.
Is the problem really just with DVD Player and I'm worrying over nothing?

Hi! I have experienced the same issues. I so happy i finally found one person with the same problem. I have also used the gamma correction and i am pretty happy with the results. As to why i get this milkiness, i have no idea. I am afraid of actually using this gamma correction thing, because i feel my settings are feirly random at times. How much do you normally correct?
Anders Holm

Quicktime MPEG IMX 625/50 export - how to disable gamma correction?

Hello,
Since there seems to be no support for encoding an MPEG IMX stream into a Quicktime container out of the box in Premiere CS5.5 I have managed to cheat IMX in there by using Quicktime component files from a Final Cut Pro installation. This seems to work fine, I now see all kinds of IMX options under the Video Codec section in Quicktime export, but there is one problem...
There is no way to edit any codec settings to turn off Quicktime Gamma correction, as you can do if you are exporting to Apple ProRes. What happens is - I need to add a Gamma Correction filter to every timeline to make it darker, because the default encoder settings automatically include some gamma correction that makes all rendered videos slightly brighter than they should be. This is a bit annoying.
Does anyone know if there is a way to disable Gamma Correction for MPEX IMX Quicktime files? Also, when will Adobe include native MPEG IMX encoder support? A lot of broadcasters in Europe (especially Eastern countries) still use IMX as their codec in their playout facilities - sometimes in Quicktime containers and sometimes in .mxf containers. Premiere needs to supports this.
Thanks!

Hi JS,
Thanks for the reply.
I can do but they're big files (about 2 to 3 gigs each - long takes!) so would take a while. I'd have to do it tomorrow now coz they're on a hard drive at the office.
John

Console to GUI, Gamma correction Woes

Is there any way in Linux that I can make gamma adjustments in an application basis? Switching between dark console fullscreens to a bright white browser window as fast as hitting a key combination is killing me! (I'm using i3).
I'm not sure I will be able to handle it. However I cannot make global gamma adjustments because that will damage the contrast of the console, and very few X applications include gamma correction settings (I only found one so far, Links2).

Currently I'm using xgamma on a couple of scripts. One of them restores to my normal settings, the other sets a darker screen. I bind the scripts to a couple of keys on i3. This works fine, but I was hoping for something more automatic.
The difficulty in hooking to an application is that I've set the browser to open on another workspace, so xgamma kicks in and I may not even want to go to the browser just yet. I also can't seem to find a way to bind the xgamma action to the changing of workspaces (that would in fact be the ideal solution), so switching back to a darker workspace doesn't restore the gamma.

Question about gamma correction

I recently ordered prints from iPhoto that came directly off my Canon EOS Rebel XT (at max quality). The resulting photos looked very much as if they were printed at PC gamma correction rather than at Mac gamma.
Is there something else I need to set in iPhoto to get the gamma I expect?

Catherine:
Welcome to the Apple Discussions. Do you have your monitor calibrated so the 2.2 gamma? I've done that and prints now look more like the monitor presentation. I've set the monitor to the sRGB profile with the 2.2 gamma.
Do you Twango?
TIP: For insurance against the iPhoto database corruption that many users have experienced I recommend making a backup copy of the Library6.iPhoto database file and keep it current. If problems crop up where iPhoto suddenly can't see any photos or thinks there are no photos in the library, replacing the working Library6.iPhoto file with the backup will often get the library back. By keeping it current I mean backup after each import and/or any serious editing or work on books, slideshows, calendars, cards, etc. That insures that if a problem pops up and you do need to replace the database file, you'll retain all those efforts. It doesn't take long to make the backup and it's good insurance.
I've written an Automator workflow application (requires Tiger), iPhoto dB File Backup, that will copy the selected Library6.iPhoto file from your iPhoto Library folder to the Pictures folder, replacing any previous version of it. It's compatible with iPhoto 08 libraries. You can download it at Toad's Cellar. Be sure to read the Read Me pdf file.

Printing and Gamma correction

I read somewhere in the aperture manuals to match the monitors gamma in prints you may need to set gamma correction to 1.1 or 1.2 in the print dialog.
If I am exporting prints to a pro photo lab am I likely to need to correct the gamma of the exported image or should I send it uncorrected?
Also, should I generally have black point compensation on or off?

I've this code :
short[] threshold = new short[256];
for (int i = threshold_level; i < 256; i++)
threshold[i] = (short) i;
BufferedImage dest = new BufferedImage(source.getWidth(),source.getHeight(),source.getType());
LookupTable look = new ShortLookupTable(0,threshold);
BufferedImageOp buff = new LookupOp(look,null);
buff.filter(src, dest);but I don't know what it's really change, if it's the input level of the BufferedImage, the gamma, the twice...
So to compare I used a commercial Software and I seen that my result is corresponding to a change of the input level of my BufferedImage and a gamma correction too. But i just want to change the input level of my BufferedImage, but I don't find example wich does that, so I try to make a gamma correction in the aim of cancel the first gamma correction produce by my LookupTable.
I hope you understand me. The aim is to make an histogram modification of a BufferedImage.
thank you

FCP Gamma Correction

This isn't something that can really be answered, I just wanted to vent a little frustration about the way Apple handle the display gamma with FCP.
From my understanding, Apple assume (and advise) that monitors are set to 1.8 gamma when running FCP, video shown in the viewer and canvas windows is then shown darker to resemble a 2.2 gamma which is how most other computer users see it, although the actual footage remains unaffected.
That's all well and good, except that I use a 2.2 gamma already because I want to see content in the same way as the majority of computer users in all my apps, and because FCP is making the video look darker I'm no longer seeing realistic results when using it. Apples recommendation to use a gamma of 1.8 to get around this seems like madness to me, why can't the gamma correction be turned off in the FCP user preferences?
At the moment I have to export quicktime files and view them outside of FCP to see what they really look like without the fake gamma correction, and then blindly make adjustments in FCP and repeat the whole process until I get the result I'm looking for - hardly a good way of working.
Apple, please give us a check-box in the preferences to stop this forced gamma change.
Paul.
Message was edited by: Videotrader

Hi Fergus
If your concern is regarding the gamma calibration of your apple display then open up the OS X System Preferences > Dsiplays pane, Choose the Color tab for the appropriate monitor and press the Calibrate button ... in the first window of the Display Calibrator Assistant don't turn on Expert Mode, just press Continue, the very next screen allows you to set the target gamma, either the Mac OS standard gamma setting of 1.8, or the PC/TV standard gamma setting of 2.2 ... step through the remaining settings and save / use your new calibration profile.
As to your actual question ... go to admit that I don't know mate! But if FCP does indeed make adjustment for your display gamma settings, it will do it with reference to your displays calibration.
All that said, your gut instint is correct, you should NOT be using your apple dispaly for making critical color correction decisions. It's totaly wasting your time. You can only make reliable critical color correction decisions when using a properly calibrated reference monitor
Hope that helps
Andy

Help with Gamma correct rescaling

So apparently Photoshop does not correctly account for Gamma when re-scaling an image, which can change the overall brightness in a noisy image:
http://www.4p8.com/eric.brasseur/gamma.html
http://www.kiransprojects.com/blog/2014/photoshop-blending-is-broken/
Is there any kind of solution in the works? Scaling does the right thing when working in 32-bit mode, but when creating things like textures for games, most work is in 8-bit mode, so switching to 32-bit mode every time I need to resize my image is not feasible.

Exactly! in a default 8-bit image the colors are gamma encoded, but when Photoshop re-sizes the image it treats it as if it was a gamma 1.0 image.
So if I have an image that has a lot of high frequency details like this UI bar:
if I then scale it down in Photoshop (which I would do if I was making an IPhone app that needed retina and non retina images, or if I just like making my images at a higher resolution and then scale them down when finalized), I get this:
when I should be getting this:
I got the second image by turning my image to 32-bit mode and then re-sizing it, which preserves the brightness in the blue area. The difference is subtle, but here is a side-by-side:
The first one is when re-sized in 8-bit mode, the second one is re-sized in 32-bit mode. you can tell that the image on the right preserves the brightness of the blue part, while on the left it gets darker.
In most cases the effect is not noticeable, but in some cases it can be very destructive on small patterns. I think most people who use Photoshop don't understand or care about the difference, but when I've explained it to my co-workers, they all agree that the expected behavior is that re-sizing should preserve the visual brightness of the image. At the very least there should be some sort of option to do gamma corrected re-sizing in 8-bit mode.

Final cut pro gamma correction

Hello.
I bet people have posted this before but after searching I could not find a concrete answer.
I have FCP 6 and Color 1.5. My display gamma is at 2.2. I edit my cut in FCP and send it to color. No problems there. I color correct in color and it looks good. I render out a quicktime. Then send the sequence back to FCP. The FCP previews it really dark. I can't do anything to change that. I go to check the rendered quicktime and it's fine, looks the same as color. If I render the final out of FCP it's also dark. This is kind of driving me crazy. Can anyone help?
Thanks.
Joey

Not that I know of. They aren't designed that way. Color is designed to send a proper signal to an external monitor. FCP is just there to show you the picture, the best it can, so that you can edit. Neither are designed for color correcting for the web.
Shane

VF0070 gamma correction - for experts...

I am using VF0070 for image analyzing - my aim is to take RGB spectrum image and transform it into reflective spectrometer graph.
I'm encountering problems regarding on how colors as seen at the computer screen are different from their REAL RGB.
I'm taking the R,G,B pixels and make a conversion to YUV for using the Y values.
I'm measuring the Dark current and subtracting it.
My reflective spectrometer algorithm is correct but still my measured graphs are not like the should appear according to the reference graphs....
my questions are:
1. What is the gamma value which is equal to 1 ? meaning NO correction... the values in VF0070 are 0 to 100.
2. What is the Non-Linearity equation of this camera?
3. How can i correct the measured color spectrum to be like the reference of the same color ?
If i knew what the camera and the driver is doing to the real color i will be able to correct the spectrum reading to be real.
If someone can help with his knowledge, I would appreciate it very much.
Thank you very much
Ofer

Ken, there's a whole part of this that isn't stated but is obvious now. You are playing back this video as a movie on the computer screen (and therefore projector), rather than as video...
So from the start it is seriously degraded by being projected that way - in resolution, gamma, and "temporality" (lack of interlace support). And yes, it would then also be affected by differences in how Macs and PCs treat their display gamma.
My comments were aimed at a situation where one can really address maximimum quality for the situation. From the above that won't be the situation here. But you can still make improvements.
You are still taking this seriously, so here's my updated advice:
Don't change anything about the production or output - keep editing to a calibrated CRT.
Do a thorough calibration of the projector as a computer monitor. The PC should have a system for this. Calibrate both color and gamma under the normal viewing conditions. The actual calibration could be on the projector and/or in the PC.
Now take bars from FCP through all your channels to where it gets played back on the PC. Use the playback software's controls to adjust the bars playback to work as close as possible to what a video display would. You won't get very close but whatever you can do will make a huge difference.
If your software doesn't have such controls, then either:
- get playback software that does, or
- (what I would do): decide the projector's role as a video display is more important than it's computer display, and adjust the projector to the bars.
If you really want to stun them, ignore all of this, get an actual CRT video projector and mount it in the room. Get a tape, disc, or true NTSC computer output device, and adjust to bars. The difference will blow you away too.

Gamma correction in Sol 10 x86

Does anyone know a way to correct the gamma value in Sol 10 x86?

(Bump)
I'd like to know how to do this myself.

Has anyone solved the "washed out colors" / gamma correction problem?

I'm trying to create a high-quality slide show from pictures. I've tried iPhoto, iMovie, and FotoMagico. What they have in common in the Quicktime engine for compression. There seems to be a problem with washed-out colors - across all programs - when trying to export the slideshow. I've tried many different codecs (H.264, x264, Photo-JPEG, PNG, JPEG-2000), as well as a variety of settings and filter corrections. Nothing has been effective. Last year, I was able to use FotoMagico with the Photo-JPEG codec, and the photos looked great. This year, things are not working (see photo below). The folks at FotoMagico attribute problems to Quicktime. And since I've tried creating the slideshow on a variety of platforms, I have to agree.
And yes, I know this is a common problem - I've read many google links - but I wanted to see if there was any current workarounds / solutions.
Any other options?
Thanks.
http://www.smugmug.com/photos/1140668576_UHnXX-L.png

Seriously Apple... this has been an issue for many years now!
Why can't this be fixed once and for all?
The ridiculous thing is that VLC play H.264 videos with much better colors than QT.
This question has been asked many many times over the years and i have yet seen a single reasonable explanation from Apple.
Here's a quick test of a color image screen recorded to a mov and viewed on screen together with the TIFF image (screen shot of everything in OS X 10.6.6)
The washed out look doesn't show as much in this simple color test but is very obvious in normal videos.
http://screencast.com/t/qQFCKZ0lgg5
1. TIFF image
2. Screen recording of above image with Intermediate Codec, viewed in QT 10 (colors not 100% but ok)
3. Same screen recording exported from Intermediate to H.264, viewed in QT 10 (colors washed out, red very wrong)
4. Same H.264 video (viewed in VLC 1.1.5)
Will this problem ever be fixed, or just ignored until no one use H.264 anymore?
Cheers

Correct gamma when using Image Adjustments Exposure?

This is a question on the gamma adjustment available in Image > Adjustments > Exposure on Photoshop CS2 for Windows.
The Gamma parameter in Image > Adjustments > Exposure seems to calculate something other than a simple gamma function (i.e. new_pixel = old_pixel ^ gamma) for the shadows.
The online help says:
"Gamma Adjusts the image gamma, using a simple power function. Negative values are mirrored around zero (that is, they remain negative but still get adjusted as if they were positive)."
Now if I create a simple 8bit greyscale gradient, then apply that function with a gamma value of 1.5 and then plot the result, I get some funny curve in the darks. If I do the same with the grey (middle) slider in the Levels dialog, I get a nice exponential function as expected after a gamma correction.
Can anyone shed some light on what is happening in Image > Adjustments > Exposure > Gamma?
Thanks a lot in advance
Martin

I cannot repro that. Here's what I do:
1. Start a new document, 256x256 pixels, sRGB color space
2. Add two vertical guides to the left and the right border, so you can snap to it
3. Make a black-to-white gradient with dithering on from left to right, snapping to the guides
4. Duplicate the background layer twice, producing layer 2 and 3
5. With layer 2 active, open Image > Adjustments > Exposure and set Gamma=1.5, click OK
6. With layer 3 active, hit Ctrl+L for Levels and set the middle (grey) input levels value to 1/1.5 = 0.6667 and hit OK
7. Now turn the visibility of layer 3 on and off --> you will see a difference in the blacks, in pixel columns 60 and below; you could also use the color sampler tool to verify the pixel values are different. For example, the pixel at x=40, y=165 has RGB=1/1/1 with the exposure tool, and RGB=4/4/4 with the Levels tool.
Note: At least on my system, the difference is MUCH more visible when I use the color profile generated by an Xrite eyeone that calibrates my system to D65, gamma 2.2, 120 cd/m^2. Without the profile, the difference is barely visible.
Martin

Correct gamma for mpeg2

Apologies if this has been answered before, but I couldn't find it.
First off, I'm using compressor 1.2. Can anyone tell me the right amount of gamma for mpeg2 files to use in coordination with DVD studio Pro 3?
For the past couple of years I've been using a gamma setting of 1.4 on all my mpeg2 encoded files. If it were any less the build from DVD Studio Pro looked washed out and milky. Anyways, with gamma 1.4, the build looked great on my comp and DVD player output on normal (interlaced?) setting. I recently got a progressive scan DVD player and found that the image was incredibly dark on my TV! Why is this? Thanks, hope someone can help.

Should I exort my mpeg2's with no gamma correction?
Perhaps, but not necessarily. If you have a workflow that you are happy with then there is no reason to change. What you want is a procedure where what you see in editing is what you get on your primary viewing device (but, of course, you do want some interoperability so that your movies still look good when you use a different playback device). Having a color calibrated workflow is the first big step in getting there.

Gamma Correction

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