RGB and color balance

I have acquired images from camera and also did extract color planes.
but images after the color extraction look like a gray sclaed images.
I am unable to extract RGB values. There is a very good explanation
by a guy called MUKS in the forums which says
"When you take a picture of the white card, make sure it is not over-exposed. Split the image into the RGB components using IMAQ Extract Color Planes. Select the same ROI on all three color planes, and use the IMAQ brightness function to measure the average intensity of the ROI. This gives you the values R, G, and B.
I donot know where do I get the imaq brightness function to measure average intensity. Can someone PLZ help me regarding this.

Hi Yesh,
I am not sure which VI muks is refering to. However, you could try GetPixelValue.vi. If you extract red color plane and then get the pixel value this should give you the R value of the RGB image. Check out this KB for a bit more information on the bit layout of RGB.
Kristen H.

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Video white balance levels not showing, so video effects and color editing won't work

I've watched white balance tutorials, and I tried clicking the dropper onto the viewer to change the color. But, in the gray box above it there are normally red green and blue lines, but I have nothing there. I think this is preventing any edits to my color balance, can anyone help?

Well, no offense, but you seriously should read the C4D help. That's normal specular shading behavior and it is uniform acroos the plane because you obviously haven't defined any scene lights and use the default viewport light. Read up on how to create materials and adjust there properties and then learn the fine art of scene lighting as well as how to use object buffers to isolate objects with multipass renders.
Mylenium

PS CC - I have a B/W background which I flattened - Then, change to RGB and add an RGB color graphic - print out makes background a greenish color - Can't figure out how to adjust.

PS CC - I have a B/W background which I flattened - Then, change to RGB and add an RGB color graphic - print out makes background a greenish color - Can't figure out how to adjust.
Thanks,
Dave

If the grayscale looks ok on screen, you are probably not setting up your print correctly. What OS? What printer?

Color Checker And White Balance

Hello Everyone.
I usually have a shot from my Color Checker and create a Profile for that Day of shooting.
I have Two choices.
1- Click on the Gray Color of the Color Checker for a White Balance, and then Export the color checker as a DNG, and create a profile.
2- Create a DNG from the Color Checker shot, and Later apply the White Balance.
In other words, when you open the Color Cheker in the Camera Raw, It Is a Flat Image. If I create a white balance from the Color Checker
and then, Export it as a DNG to create a Profile Is It more Accurate ?
Dose It make any different ?
NOTE:
I get a better White Balance shooting either the Gray color from the Color Checker, Or a 18% Gray Card, rather than shooting a white color of Color Checker
or Shooting a white paper.
UPDATED:
I was reading this article that you should Aim the Gray-Card one third of angle between Camera and the Main Light or sun.
It says If you hold it flat next to your object It is Wrong.
Is this also how you should Aim the Color Checker One third of angel between Camera and the Main Light ?
Please read this article.
What's a Gray Card and Why You Should Own One
Also this Article Is opposite of the top
Using Gray Cards
Thank you very much For All Your Helps.

In your initial post you seem to be asking if it makes a difference whether you set the WB on the DNG you create your color profile from or not. I don’t know that it makes a difference in the color profile but it should be easy enough to test experimentally, by making two DNGs from the same raw file, one where you’ve set the WB to as low as it’ll go, and one where you’ve set the WB to as high as it’ll go, and make a profile from each and see if you get a different look based on which one you use or not.
Then you talk about which gray patch on a color-checker is better to use for WB, saying you don’t use the white one, but one that is grayer. My idea is to use whatever patch matches the brightness of whatever you are wanting to get the closest to the right WB. If you have a midtone subject then use the midtone gray patch. If you have a light subject use a brighter gray patch, and if you have a very dark subject then maybe use a darker patch, though probably not the darkest because there will be more error in that WB computed from the darker patches, so lighter ones would be preferred if you don’t have any other reason to choose one over the other, though not the brightest one, necessarily, because it could be clipped and unusable.
Finally you’re asking about the angle of the card with respect to the camera and the mainlight. You don’t want it to be halfway between the angle of the mainlight and the camera because that would have too much glare to the extent that there is any glare with the specially-prepared surfaces of the color-checker. You also don’t want it to be flat on to the camera, because that gives too much emphasis to the lighting behind the camera position (blue sky, green plants, red dirt, building walls) as blocked by the camera operator, so 1/3 of the way toward the mainlight angle is a way to mix in the lighting along the horizon with the mainlight to get an average. If you doubt whether this makes a different take two CC shots, one flat toward the camera and one facing the mainlight, as the two extremes of the color balance variation and see how much different they are when eyedroppering the same gray patch in LR.
In your situation, with 100% strobes, your only non-strobe-colored lighting would be from reflections of the strobes off other things nearby. Are you in a completely neutral studio setting and everyone except the model wears neutral clothing? If there are close by light colored neutral objects such as walls and ceilings, then some of the strobe light will likely reflect from the clothing and off the walls making the color-balance tinged with a bit of the subject’s colors. You could minimize this by taking your calibration shots without the subject or any non-neutral-colored objects in the vicinity of the strobes so as to minimize the subject reflection coloring the light. Whether any of this matters depends on how neutral and reflective your studio environment is. If your entire studio is matte black except for the model and backdrop then you don’t need to worry, but if it’s not, then there would be some reason to care.

How to select matching RGB and CMYK colors

Starting from scratch for a client, how do I select matching RGB and CMYK pairs?
Say we find a nice red colour in RGB for screen use, how do I then find the correct CMYK for print? And what assumptions do I have to make when doing this, if any?
Would it be the same for the other way around (choose CMYK first for print and then find the RGB equivalent)
Is it more sensible to start with a Pantone colour and then find the RGB and CMYK equivalents for that?
Many thanks
RobbieG
(I'm working with Ai, Ps and Id CS6)

Yes. Better to start with Pantone reference books where you are viewing the color in a reflective environment. As already mentioned, color on the monitor can be deceptive. And, I think the others are basiclt saying that you should have everything calibrated and use color management policies in your apps. There is a way to find CMYK equivalents using Photoshop's color palette. Let's say you have an RGB Red as the foreground color in Photoshop. If you double click on the swatch you will get Photoshop's color palette which lists the RGB percentages, CMYK percentages, LAB percentages, and HEX web color for that Red. You can go further and select "Custom" and the Pasntone Spot color palette opens and gives you the closest Spot color value for that Red. This however, depends on your color settings. That's why I recommend you start with the Pantone swatch book and get the perecentages of CMYK from their formula guide which is set to industry standard color.

I am using PS cs6 and lightroom and I am having a hard time know what color space to choose. The lab that I am using told me that their color space is sRGB. Do I need to have both PS and Lightroom set at sRGB or should I have PS set at adobe RGB and jus

I am using PS cs6 and lightroom and I am having a hard time know what color space to choose. The lab that I am using told me that their color space is sRGB. Do I need to have both PS and Lightroom set at sRGB or should I have PS set at adobe RGB and just set my export from lightroom as sRGB?

Please post in the Photoshop forum.
http://forums.adobe.com/community/photoshop
Bob

Blue color balance with iSight and Java

I have seen this question posted before - with no real answers, only suggestions that had nothing to do with the problem. Here's whats going on - internal camera and any connected Firewire camera works fine on iChat, PhotoBooth, IMovie, etc. Use those same cameras - internal or external- on a Java based web page and the image shifts to a blue monochrome. Not the blue you get with incorrect color balance from lighting, but nothing but blue hues. I can take the same Firewire camera and hook it to my G4 laptop running the same OS (10.4.8) and it works fine on the Java sites. Problem only occurs with Intel iMac and ANY camera. The problem appears to be the way the OS intergrates with Java (via Quicktime, or is QT out of the picture when using Java?)) on the Intel computer.

I have looked on MacFixIt for both Blue Screen in Java and just Blue screen and have not turned up any results.
11:46 AM Wednesday; December 27, 2006
Happy Holidays

Bayer Filter and colour balance.

Hi all.
I have recently been acquiring images using a mikrotron MC1363 camera and LV code 'Grab and save to AVI'. I have then used ImageJ to create a stack of U8 images. My problem then arises in that I need to apply a bayer filter and colour balance to the images. I have been sent a correction matrix by mikrotron and extracted pixel intensities from the U8 images, but am now stuck. I don't know how to use the information accrued to give a debayered image of true colour. Any advice would be great.
Attached is:
Tthe MC1363 manual
The matrices supplied by mikrotron (lupa1300)
An image folder containing:
-A true colour image
-A snap taken using the MC1365 of the true colour image
-Images of the colours red, green, blue, white and black extracted from the bottom right hand image, as u8 jpegs.
Thanks.
Dan.
Attachments:
992-EoSens 3CL-MC1364-65-Manual.pdf ‏795 KB

Hi Danbubbles,
The pixels of the Bayer filter are arranged in a checkerboard pattern on the sensor. There are twice as many green as red and blue pixels in order to mimic the higher sensitivity of the human eye towards green light.
Due to the filter each pixel measures only one color. The two remaining colors are estimated (interpolated) using the eight surrounding pixels. This technique is called Bayer demosaicing or Bayer to RGB Conversion.
http://www.stemmer-imaging.co.uk/en/glossary/5287-Bayer-Filter
As far as I'm concerned there exit different "de-bayering" algorithm, which are different in terms of quality and performance, but in general
0#
you "move" a structuring element - which is like a subset of your input-image - across your input-picture starting at row = 0 column = 0, which is indexing the same pixel in both of your input AND output-image: http://www.mathworks.de/help/images/morph6.gif
1#
then you calculate a new value for this particular pixel in your output-image via interpolating the indexed pixel and its adjacent pixels in the input-image, e.g. like described in this pdf:
http://www.matrix-vision.com/tl_files/mv11/Glossary/art_bayermosaic_en.pdf
2#
then you move on to the next pixel which should be at row 0, column 1
repeat, until you reach the pixel at row n, column m
Regards,
Alex
♜♖ LabView 8.6 - LabView 2014 ♖♜

Using PS to edit in LR screws up color balance?

I'm sure I'm missing something obvious here, but I can't imagine what it might be.
I start with an image as a .NEF file (Nikon Raw format).
If I import the image into Lightroom (3.4) and export it as JPEG without changing anything, it looks fine:
If I import it into Photoshop (CS5) and save it as JPEG without changing anything, it also looks fine:
If I enter control-E in Lightroom to ask Lightroom to launch Photoshop to edit the image, it looks fine on screen. However, if during editing I ask Photoshop to save the image as JPEG, the color balance is much different than it was in either of the other two examples:
What am I missing here? To my knowledge, I am not changing color balance in any of these images.

Incidentally, the three images I posted here look much more like each other in my post than they did originally. When I view them directly, the first two images look basically identical; the third is much colder and darker. This difference seems to vary depending on which program I use to view the images. For example, there is a lot of difference if I use Picasa to view them, and much less difference if I use Windows Picture and Fax Viewer.
If I open the images in Bridge, I see that each one has a different color profile! The one saved from Lightroom says sRGB, the one directly from Photoshop says Adobe RGB (1998), and the one saved from Photoshop within Lightroom is ProPhoto RGB. I'm guessing there's an FAQ somewhere that explains the differences between these; can someone please point me there?

Color balance looks different going from lightroom to photoshop which is correct?

color balance looks different going from lightroom to photoshop which is correct?

Besides calibrating you rmonitor:
Make sure that in PS you have selected ProPhoto RGB as Working Space.
Go > Edit > Color Settings.
LR uses ProPhoto RGB and tht cannot be changed. So you have to make sure that PS uses the same Working Space.
WW

Adobe Camera Raw: calibration and color accuracy

"In this article I report the accuracy reached with the above scripts in my calibration effort, some validations in different lightning condition and the impact on new color balance caused by the adjust sliders and the tonal curve movement."
If someone has an interest.
Link to Article
Ciao
Marco

Chris,
>>>
The ICC uses LAB D50, as does Photoshop.
Marco,
>>>
(prof. Boscarol) on his forum:
>>>
1.Lab is not absolute and there are infinite Lab.
>>>
2.The illuminant E is a theoretic reference illuminant
I must disagree with the implied conclusions in both statements, but with a friendly, not confrontational tone. And, Adobe and other software may be assuming Lab is D50. I cannot and would not dispute that.
What I said is that if you follow CIE math, the color values in Lab mode will be at Illuminant E. I stand by that conclusion. But there is little in the way of enforcement when it comes to standards.
Lets start with the CIE color values from measurement to numbers. This is the illuminant times the subject (measured) times the standard observer. It requires matrix arithmetic because the operations have to span the visible spectrum. So it is a little more involved that simple multiplication, but that is not conceptually important at this point.
The light source may be defined by a standard such as D50 or D65 or it can be provided in a custom set of tables (from measurements). The subject (raw image) values are adjusted for the measurement instrument to represent illuminant E (equal energy). This would be the spectral response of the color filters and such in an image sensor. The standard observer values are provided by the CIE, again at illuminant E. The resulting XYZ values are at the white point of the illuminant used for the source light.
Before moving on, the image sensor spectral response tables are too often not available. Thus assumptions are made that make calibration so bloody difficult. Enough said.
These XYZ values are then transformed to Lab values. The math in this step effectively removes the original light source from the XYZ values, resulting in illuminant E. This is how it is described in the literature, Berns, Hunt, and Wyszecki. If one adheres to the rules, Lab will always be illuminant E. XYZ values without a white point definition are as meaningless as RGB values without a profile definition.
But there is no enforcement body. I have seen lots of code that does not adjust for the XYZ white point at all. In that case, there would be an infinite set of possible Lab white points.
If you assume Lab is always D50, D65, or whatever floats your boat the transforms from RGB to Lab to RGB again would not be compromised. The ICC does define a white point in each ICC RGB profile. So if the input colors are correct, the output colors will be correct. It isnt too important what white point is used for the intermediate step.
But if you take a file in Lab mode from some other source, the white point would be very important. If I give a Lab file to Fred in E and Fred assumes it is D65, color conversions will be wrong. If Fred creates one at D65 and hands it to Adobe, chaos reigns. The ICC does not have a profile for Lab mode that I am aware of. So I dont know that the ICC attempts to trump the CIE as suggested. If someone knows of a verifiable reference for this, I would love to hear of it. The TIFF metadata does have a tag for white point. But I have never seen it used in a Lab mode file, including Adobes.
Illuminant E is no more or less theoretical than any other Standard Light Source. But it is at the core of all color matching algorithms and the basis of the standard observer target values. It is most often simply referred to as the equal energy light source so it might not ring a bell like D50 or D65.
The conversions between Lab and LCh and the algorithms for Delta E 2000 color differences are all implicitly dependent on Lab values at illuminant E.
I rest my case.
Cheers, Rags :-)

Color Balance Changed with Update

I have some HD Test pattens that I use to calibrate my video projector with via my AppleTV and my Win7 computer. Both are connected to the projector via HDMI though a switcher unit. The Projector sences a different input when the swithcer is changed allowing me to set indivigual balance levels for the ATV or Computer.
Unit the update the settings were very close between each unit. The Win7 machine has perfect color balance through Red Green and Blue filters. The ATV was never perfect but very close.
Since the update, and here nothing has changed except the update, the ATV colors are well off running the same test signals. The RGB levels are out. I have tried each of the 3 signal feeds from the ATV in the settings menu, but nothing.
The colors now seem to be too vibrant and look false. I can componsate for this in the projector, but why did it change?
Has anyone else noticed this? Again all that changed was the update!!
Nathan

The closest I could getting it back to the same colors before the upgrade is changing it to the RGB Hi setting, and limiting the HDMI Color in my projector to Limited, then adjusting the Brightness very slightly. Everything now is much closer to the correct color balance through Blue test glasses. Still not as perfect as it was, or running off my Win7 machine.
Nothing has changed in my setup apart from the ATV Update. Do they not check this stuff!!
Nate

I need the LR equivalent of the PS red slider in color balance

For some reason all my studio portraits need the red slider in PS to go down 6-10 points. But I cannot figure out how to reproduce that in LR. I've tried the camera calibration but it doesn't seem the same. This is a HUGE problem for me. Any help would be greatly appreciated. I'm runing lr4 and cs6. Thanks.

adjohnson1414 wrote:
I just wish wish wish that LR had color balance sliders like PS.
As Tom Rockwell already mentioned the RGB Tone Curves will provide very similar capability PS's Color Balance sliders. Go to the Tone Curve, click on the small icon in the lower right corner of the panel, and select the 'Red' Channel. To emulate the "midtone" Red/ Cyan Color Balance slider grab the curve at the 50% point and lower it to decrease red midtones.
That said I would agree with Web Weaver that your White Balance is off for your studio lighting setup and suggest using the White Balance Sliders for correcting it. You can then save it as a Develop Preset using only White Balance and perhaps Camera Calibration 'Profile' settings checked. Using a white balance card or ColorChecker Passport (above) will give you much more accurate results.

Color Balance No Longer Works

Hi! I'm new to the forum.
I used an add-on for Photoshop that creates an engraving effect for images. I made the image greyscale to do the action, then duplicated the end result in a new file and converted it back to RGB mode. Now there's something wrong with the color balance and other tools to change the color. Additional info:
1. When I try to change the color balance, sometimes it reverts to black and white, and sometimes the result is changed, but looks nothing like the preview from the color balance window.
2. I can add colors to the layer by using paint bucket - they look normal.
3. I've tried saving the file in various file types and opening it again (.jpg, .pdf) - no change. I even used my print function to save the file as a .pdf, then opened it again in Photoshop - I still have the same problem.
4. I've tried closing Photoshop and reopening it - no change.
5. I open other files of mine and I don't have this problem.
Help!
Thanks everyone!

BOILERPLATE TEXT:
If you give complete and detailed information about your setup and the issue at hand, such as your platform (Mac or Win), exact versions of your OS, of Photoshop and of Bridge, machine specs, such as total installed RAM, scratch file HDs, video card specs, what troubleshooting steps you have taken so far, what error message(s) you receive, if having issues opening raw files also the exact camera make and model that generated them, etc., someone may be able to help you.
Please read this FAQ for advice on how to ask your questions correctly for quicker and better answers:
http://forums.adobe.com/thread/419981?tstart=0
Thanks!

How can I convert from color balance in FCE to color balance in FCPX?

Let me start off by saying that I've been having an issue with a project in Final Cut Express - a project I'd put a lot of time into and thought I was finished with. Before continuing on, I encourage you to take a look at my other thread: https://discussions.apple.com/message/18702933?ac_cid=op123456#18702933
Realizing that there may be no one who can walk me through fixing my project as is, I decided to download a trial version of Final Cut Pro X and see if I could replicate my project there and have more success (after all, it was only a matter of time before I switched anyway).
So, in my original project in FCE, I keyed a lot of frames with different color balances. I downloaded the Ripple Training color balance effect to do just that, but the sliders are set up differently. In FCE, they range from -1 to 1. In FCPX, they range from 0 to 1. I'm wondering how I can conveniently convert the values from FCE to FCPX. Being terrible at math has made this much harder.
Just by drawing a diagram, like the following, I can figure out the basics:
FCE
[-1]-----[-.5]-----[0]-----[.5]-----[1]
is equal to:
FCPX
[0]-----[.25]-----[.5]-----[.75]-----[1]
Since I have very specific numbers, not all of which can be easily converted using a basic diagram like the one above, I definitely need some help here. For example, one of the values in FCE is .77. What would that be equal to in FCPX? It's probably something simple, but like I said, I'm stupid when it comes to math.
Thanks to anyone who can provide me with some help here, although I still hope that I'll end up having no reason to redo everything in FCPX.

Well, the "math answer" is .885…but I'm afraid that's not likely to be of much help. FCPX and FCE have absolutely nothing in common, including filters land color correction. So even if you sent the time comverting all your numeric values, I'm guessing you'll wind up with a mess and be very frustrated with all the time wasted in the workaround.
If I read your original FCE thread correctly, I if it were my project., I'd do a test on a short clip in X to see whether yoi can the effects and quality you expect. If you can, great. Build you project from scratch and learn a new NLE at the same time.
Good luck.
Russ

RGB and color balance

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