Grayscale to RGB Confusion

Hi guys, please try this:
1) new image, grayscale
2) fill (say 96,96,96)
3) image->mode->rgb color
The pixels will be (95,95,95) and (96,96,96) when they should *all* be the same.
It also happens when you paste a black & white image into an RGB document because even though it has three 8-bit channels (by definition not grayscale) Photoshop decides to make it grayscale.
Is there a way to correct this ?
Thanks.

Hi,
My Color Settings are set to Monitor Color, and the Proof Setup is set to Monitor RGB.
I don't see any settings for dithering.
When I say Black & White (as opposed to Grayscale) I mean a 24-bit RGB image that has only gray (R=G=B) pixels. If I paste that into an RGB document I get pixels that are not consistent, if I paste it into a grayscale document the pixels are consistent but become inconsistent when I convert that document to RGB.
What should I do ?
Thanks for trying to help.

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Grayscale to RGB

Hello,
I am trying to convert a grayscale image (pixelBits = 8 numComponents = 1) to an rgb image (pixelBits = 24 numComponents = 3).
There are many tutorials to convert RBG to grayscale but not the opposite...
Any idea ?
Thanks.

Hi Yann,
Thanks for your useful post.
Unfortunately there's still little defect : result operation colormodel is not explicitly specified, which leads to strange background rendering when using backgroundValues parameter in "rotate" operation.
So here the enhanced code :
PlanarImage src = JAI.create("fileload", "Photo.jpg";);
System.out.println(src.getColorModel());
// Prepare operation parameters
double[][] matrix = {
     { 1.0D, 0.0D },
     { 1.0D, 0.0D },
     { 1.0D, 0.0D } };
ParameterBlock pb = new ParameterBlock();
pb.addSource(src);
pb.add(matrix);
// Prepare rendering hints
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_sRGB);
ColorModel cm = RasterFactory.createComponentColorModel(
     DataBuffer.TYPE_BYTE, cs, false, false,
     Transparency.OPAQUE);
SampleModel sm = cm.createCompatibleSampleModel(image.getWidth(), image.getHeight());
ImageLayout imageLayout = new ImageLayout();
imageLayout.setSampleModel(sm);
imageLayout.setColorModel(cm);
RenderingHints renderingHints = new RenderingHints(null);
renderingHints.clear();
renderingHints.put(JAI.KEY_IMAGE_LAYOUT, imageLayout);
// Perform the band combine operation.
PlanarImage dst = (PlanarImage)JAI.create("bandcombine", pb, renderingHints);
System.out.println(dst .getColorModel());

Converting Grayscale To RGB

I am trying to add some B&W photos that I scanned. In a previous post I was advised to convert any grayscale pix to RGB. Is there a way to convert using os x 10.3.9? I think I figured it out in photoshop. When I open the pic in preview and select "get info" the profile reads "sRGB IEC61966-2.1". Is that ok? Someone please help lol. Thanks in advance.

Yes the sRGB profile is fine.
Regards
TD

CMYK RGB confusion

Recently I have had to get myself involve in work for print and coming from a digital background I have a very a very tenuous grip on the working of getting material ready for print.
Recently while scanning a forum on a totally unrelated subject I spotted these two quotes from two different people.
'unless you have experience preparing images for commercial print and your client has specified CMYK for offset printing DO NOT supply CMYK images - stick to RGB output.'
'yes i wouldnt use CMYK images.
because most/all printers have there own convertion algorithms so the printer will convert a CMYK image back to RGB then convert it back to CMYK.
so you will lose a bit of quality'
This confused me as I have always been told to supply CMYK. I have a very vague recollection that this has been mentioned to me before by a client but this is so vague it might as well have been a dream and was before I started getting involved with print. I just wondered if anyone could clear this up for me.
Thanks for any help.

Jim,
It's a bit of a free for all out there. The best course of action is to have a discussion with the printer you plan to use and get on the same page. They may insist on RGB or a certain flavor of CMYK. In general, though, I find that if I supply CMYK files, most printers usually just sends those files straight through, without doing any conversion. If they convert them and the color gets whacked, it may come back to haunt them. Some printers know how to handle and convert RGB files properly, and others do not. I've done a fair amount of this, and personally, I would always prefer to supply CMYK files so I control the conversion, but I'd have a discussion with the printer first or look for clear, precise specs (and preferably their custom CMYK profile) on their website (which many don't provide).
That's where the contract proof generated by the printer can come in handy. If you insist on a contract proof, then sign off on the color, placement, layout, etc, the printer has to hit that target on press within reasonable tolerances, otherwise you are eligible for a free reprint. Those tolerances can be fairly liberal, but decent printers usually come very close to matching their own proof.
As Rick McCleary mentioned on another thread on this forum.....we are neither 'here' nor 'there', but somewhere in between in the evolution of digital printing. That won't change fast, I'm afraid. Too much legacy equipment, approaches, etc.
Lou

How to export grayscale (not RGB) from LR3

I am processing hundreds of scanned B&W negatives and want to work on them in Lightroom. However, grayscale is not an option in 'export', so I have to export as RGB (@ 3 times the size), then open them in Photoshop, and change them back to grayscale - a crazy convoluted workflow!
Am I missing something, or is there really no way to export grayscale out of Lightroom?

I would like to find a plausible explanation as to why a color scan of a monochrome original is better than a monochrome scan. It is a thoroughly established law of physics that the information content of a fully predictable signal is zero. What I mean is that if the R, G and B channels of the monochrome are identical, then “upgrading” from a single-channel scan to a three-channel scan produces perfectly predictable results (two additional channels, identical to the first one) and NO new information. But what if the R, G and B channels of the monochrome are not identical? What is the cause and source of this difference?
Assumption 1: all sub-pixels (RGB) of the scanning head are co-located (scan precisely the same spot of the original). In this case any difference between the color channels is simply processing errors (nonlinearities, inter-channel differences in calibration), and a 3-channel scan produces no new information over a 1-channel scan.
Assumption 2: the three sub-pixels are slightly offset to each other. In this case each channel scans a slightly different set of spots from the original, and combination of the three channels might produce additional information (extra resolution, if the channels are properly combined).
Further along this line of thought: I guess assumption 2 is correct and the three sub-pixels are slightly offset to each other. Perhaps all scanners are designed to work with color originals and the conversion to monochrome in the scanner is less than optimal, and should be done in post-processing rather than in the scanner? Another line of thought: even if the original and its digital representation are monochrome, we are using three-color monitors to view monochrome images. Operating systems use technologies (eg Microsoft’s Crystal View) that use the three-color sub-pixels to antialias black-and-white text. Because humans’ visual acuity for color is much lower than the acuity for monochrome, the colored sub-pixels used for antialiasing are not normally perceived as colored blotches but rather as smoother gradations in grayscale. Along this line of thought, it might be possible that a three-color version of a monochrome image produces smoother gradations of tone than a monochrome version of the same image does, when viewed on a three-color monitor.
Just speculating, of course, in absence of solid knowledge.
Antero

Acrobat grayscale images editied in photoshop convert to rgb when brought back into the pdf file.

After I edit a photo using the object touch up tool in photoshop CS6 and bring it back into acrobat as a grayscale halftone all works fine till I print. It prints on multiple plates. When I edit it again in photoshop the halftone has turned into RGB. It happens every time. I assume there is a color setting in acrobat that is doing the conversion from grayscale to RGB but I don't know where to look. This has worked fine for years and has only recently stopped working. By the way I'm using acrobat pro.

It's really necessary to know by which program you had created the PDF.
Here comes a test PDF for questions like yours, created by InDesign:
http://docs-hoffmann.de/riptest05072013.pdf
Different images:
sRGB, pRGB=ProphotoRGB, CMYK , all with individually embedded profile,
Grayscales: without embedded profiles, because InDesign doesn't embed gray profiles,
Lab: without profile, because Lab is automatically detected and not ambiguuos.
Of course, using so many different images in one PDF is useful only for tests.
An actual test:
Touch Up Object Grayscale and edit in Photoshop. There is no embedded profile
but the image is in PS detected as Grayscale. One has to assign a profile.
Re-imported in the doc, it is a Grayscale JPEG*, before it was a Grayscale ZIP.
In Acrobat 8 one can check the actual content of a PDF by
Advanced > Print Production > Preflight
In newer versions this is still available but somewhere else.
I'm using version 8, because I uninstalled X on purpose.
Best regards --Gernot Hoffmann
*Edited:
As far as I remember, there is no special code for Grayscale JPEGs, it's just a JPEG
with zeros in the Cb Cr channels ... like an R=G=B gray image.

Convertir une image "Grayscale I16" en "RGB U64"

Bonjour,
je cherche depuis un petit moment sur tous les forums que je connais, et je ne trouve pas de réponse à mon besoin, à savoir convertir une image en niveaux de gris de 16 bits en RGB 64 bits. J'ai réussi à le faire en 32 bits, mais la dégradation est trop importante pour mes besoins.
Si vous avez une solution, je vous en serais reconnaissant.
Si ça peut vous aider, j'ai Labview 8.6 et NI Vision.
Merci d'avance

Si vous souhaitez, voici le VI que j'essaye de faire.
Il marche très bien en grayscale 8bits => RGB 32 bits, mais pas en Grayscale 16 bits => RGB 64 bits...
J'ai supprimé tout le traitement que j'effectue sur l'image pour que ce soit plus lisible. Comme j'effectue divers traitement suivant la couche de l'image (R,G,B), je suis obligé de passer par un Imaq ReplaceColorPlane.
Merci du temps que vous consacrez à mon problème.
Pièces jointes :
tests.zip ‏217 KB

Save for Web... and grayscale images

I noticed a strange behavior when I use "Save for Web and Devices" on scanned BW negatives...
I import the negatives via the scanner's twain driver in Photoshop as 16bit grayscale images. My grayscale working space is normally set to the default DotGain 20% profile. When I want to show these images on the web, I use "Save for Web and Devices..." and I have selected the convert to sRGB option. For some reason, the "embed color profile" option is disabled (grayed out) when the document is in grayscale mode.
When I view the the exported image (in a color managed application or browser) it looks too dark and shadow detail is lost. Examining the file info shows that the JPG file is in RGB color space and has the sRGB profile assigned.
When I convert the image to RGB mode before I do save for web... the exported image will look exactly like it looked in Photoshop. Also, the mode change doesn't cause a change in appearance. Also, after changing to RGB, the "embed color profile" option in save for web... becomes enabled.
I experimented with other working color spaces and noticed that an image exported from a grayscale image in "GrayGamma 2.2" working color space will display almost like an image that was exported from a grayscale image converted to RGB.
I would like to understand this behavior and whether it is correct. My assumption would be that a conversion to sRGB during the export should yield the same result like a manual conversion of the image in photoshop but for some reason the results are quite different.
How can I export my grayscale images to sRGB JPG without having to convert to RGB manually while preserving the tonality from the original image?
I have attached an image which I hope might illustrate the effect I'm describing. The crop on left hand side looks as expected and is the result of exporting from an image that was converted from grayscale to RGB mode (sRGB working space) before using save for web...
The image in the middle is the result from converting to GrayGamma 2.2 color space but leaving the image in grayscale mode before saving for web and devices. It is almost identical to the crop on the left. The crop on the right hand side is the result of using save for web and devices from the original image in grayscale mode with the default DotGain 20% profile.
Thanks
/lars

These are my settings. Are they the same in your SFW dialog?

I can change from grayscale slider to hsb slider

I did a grid in photoshop using a tutorial in this website http://www.webdesign.org/web/photoshop/textures-&-patterns/grid.3792.html and I got it, but now a want to to a boder for each grid but the Grayscale slider prevails and all of the others sliders are off. I go to the color palette and click at the top right of the palette and a menu appears the with options like grayscale sliders, RGB Sliders, HSB slider, CMYK Sliders, Lab sliders, and HTML sliders the online one on is the Grayscale sliders after that all of them are off
The layer menu is off completely, and some other features in the photoshop cs3, and when I go and save the file the GIF, JEGP and all other common formats are off, I can't save the file on those formats because psp, photoshop pdf and other that I am not interested on. I want gif, jegp etc.
I have just realize that when I created a new documents I might put it in the grayscale mode only.
What do you think about it guys I want to be able to apply boders and save it in gif, jepg and other common format

There aren't many reasons why you would start out with a grayscale document, even if you want only a grayscale image because RGB gives you more control so make sure that Color Mode is RGB Color

Why use "Don't Color Manage This Document"?

Hello,
I work on photos, mostly black and white, that will be either digitally or offset printed. I have been told that I should not assign any color profile to these photos in PhotoShop. I should instead choose the option in Assign Profile to "Don't Color Manage This Document."
I think the reason is that we do not want the RIP to interpret any color profile that may be in the RIP and apply it to the photos. But I really don't know why I should use this opiton.
Can anyone educate me on this question?
Thanks,
Tom

Tom,
You've left a few potentially important details out of your scenario, but I will give you my thoughts. Are your B&W images 4/C CMYK, grayscale, or RGB? It can make a difference.
When editing images for my own fine art printing, I always tag it with a profile. In fact, I do this whether my image is grayscale, CMYK or RGB. Of course, I am doing the printing myself, so I have full control over the project. I use a Canon 6100 and custom RGB profiles (which I build myself), so most of my B&W or toned monochrome prints are RGB. Without a source profile, Photoshop will have to assume or assign a profile in order to make the final conversion.
I have used B&W RIPs before, such as QTR, and they don't speak ICC. They simply take the raw umbers in the file and output them to the printer, passing them through specific inking recipes (which they tend to call profiles, but this is very confusing to users, because they can be confused with ICC profiles, which they definitely are NOT). In this case, the RIP simply ignores any embedded ICC profile and just outputs the numbers.
More traditional RIPs (Poster print, Studio Print, ColorBurst, etc) can properly interpret incoming CMYK data with an ICC profile and make whatever conversions are necessary to give you an accurate print. Of course, accuracy depends on having accurate profiles for monitor, printer, paper, ink, etc.
So, if we are talking photos destined for fine art printing on an inkjet, I normally would tag my files with an ICC profile.
I recently designed a job for a client using InDesign. It included a lot of photographs, illustrations, and native components created using Photoshop, Illustrator, and InDesign. The problem was that the customer had not selected a commercial printer, so I had no idea where the job would be printed, on what type of press, ink limits, paper stock, etc. What to do? I chose a middle of the road profile (IDEAlliance SWOP2006_Coated3v2) which has an ink limit of 300 and assumes a #3 coated sheet. I left this profile active in InDesign. I edited my files in Photoshop and Illustrator and tagged all images with the same profile, and placed them into InDesign. So, all components had the same "generic" CMYK profile based on a middle of the road industry standard (I use the term standard loosely). Having all components tagged enabled me to generate an accurate, high quality color proof on my inkjet (assuming the final press will adhere the the above SWOP standard).
Before submitting the file, I converted it to PDF/X1-a using Acrobat Pro. This strips all profiles from the file, but names the intended color profile in the PDF file. So, I was supplying an untagged file, but if they wanted to, they could see what the intended profile was. I stripped the profile because I did NOT want the unknown commercial printer to convert my carefully generated files. One concern was that all items on the black plate (black text, lines, vector art, etc) might somehow be converted through Lab to a new CMYK profile, thus giving me CMYK separation of my blacks, potential registration problems, etc. To cover my butt, I supplied my color proofs with the file and told the client the final job should look very close to my proofs if the printer did his job right. It also gave the printer a guide print to help them get it right. So, to me, that is the major reason to supply an untagged file.
Sorry for the long diatribe.
Lou

Form wizard cannot detect fields

I designed a form in InDesign CS4 and saved it as a high resolution PDF file. I open the PDF file in Acrobat 9 Pro and go to Forms > Start Form Wizard, select the current document and get the error message: "No new form field annotations were detected."
I have created forms this way in the past and this is the first time this process hasn't worked for me. Any suggestions on what could be causing the problem? (Do I need to export the PDF a particular way or something else?)

Exporting from InDesign with printer: Adobe PDF and PPD: Adobe PDF 9.0
Paper: Letter
Crops: Off
Output Color Settings: I have tried Composite Grayscale, CMYK, RGB and Separations (Black)
Graphics: All
Fonts: Complete
PDF Default settings: I have tried Standard, High Resolution Print, PDF/X-1a:2001, Press Quality, Smallest File Size, Standard
For example, I have tried combinations such as exporting as black separations with the Press Quality setting or as a Composite CMYK image with the PDF/X-1a:2001 setting.

Help with Photomerge and how to do suggested solutions

I am using Photoshop CS3 on Windows XP and am having a problem with Photomerge working very slow, not working at all, and not being able to handle more than 2 photos (sometimes it won't even do 2 that have 25% overlap). I found these solutions in a previous thread.
Solution 2: Increase the amount of scratch disk space available to Photomerge.
Solution 3: Decrease the size of the source files.
Solution 4: Reduce the amount of RAM allocated to Photoshop in the Memory & Image Cache Preference to approximately 40-50% and retry.
Can someone tell me if these solutions are correct? If so, how can I do these? If not, what can I try? If I could get detailed instructions (I don't know anything about computers) that would be the best. Thanks in advance for any help!

I have often scanned LP album covers in segments, at 600 ppi, and used Photomerge to meld them together. That results in images that are roughly 7200x7200 pixels, or 50 megapixels. Photomerge is pretty quick, given the size of the files.
But yeah, you may need to reduce the resolution of the files you are scanning. You may be scanning at 1200 ppi or higher. For text, I don't think I'd go much below 600 ppi if you want a really clear reproduction, and scan in grayscale or RGB, not the "text" mode, which is 1-bit bitmap and will not likely work well with Photomerge. Turn all descreening or sharpening options off in the scanning software; likewise, turn off all exposure wizards and expose all images at the base manual settings (don't use the scanner software's curves, etc.). You will take care of the exposure, sharpening, descreening, etc. in PS once you have scanned and merged.

Change color of scanned line art

I'm want to scan a line art of a leaf, make the white background transparent, and change the black lines to red. I can scan the art to Photoshop, get rid of the white background, but I can't change the black lines to red. After scanning, the background layer is locked and won't allow editing.I tried scanning as a bitmap, b&w scalable, 16 color, etc. Nothing works.

Image > mode > grayscale, then image > mode > RGB. Then create a solid fill layer layer > new fill layer > solid color. Pick your color and set that layer's blend mode to screen.
Not sure how you're deleting the background, while keeping the leaf on the background layer. But if you make it a grayscale or RGB image, you should be able to convert the background layer by going to layer > new > layer from background.
If you do manage to get the layer off the background you can clip the solid fill layer to the leaf layer by having the solid fill layer active and pressing ctrl-alt-g, or by alt-clicking the space between the two layers in the layers panel (you'll see you cursor change).

Halftone or Line art figure

Is it possible to find whether a figure is Halftone or Line art using scripting.
thanks,
Sashi

Are you referring to the documentMode bitmap (1bit depth) as opposed to grayscale/rgb or do you mean checking whether any pixels in a grayscale- or rgb-image have values other than 0 or 256?
In first case a simple if-clause works:
if (app.activeDocument.mode == "DocumentMode.BITMAP") {
alert ("bitmap")
else {
alert ("not bitmap")
In second case you might use the histogram.
Though your use of the term »figure« seems a bit odd to me – are you talking about an image or part of an image?

In the Info panel, how do I display pixel values as values, not as percentages?

I'm trying to show, using the eye dropper tool, the actual values of pixels in an 8-bit grayscale image (Mode command confirms that's what's there). In the Info panel, the eye dropper tool displays percentages for every type of color information (K, CMYK), while the "8-bit" field remains blank.
I've looked at Properties and pretty much everything else that I can find with no luck.
Photoshop CS6, 64 bit, Win7-64
Thanks!
Ian J.

Ian Jaffray wrote:
Noel,
Thanks for your reply. I thought this had been fixed by recreating the Preferences file, but this morning I was back to percentages. I did have different settings in the Info Panel from the ones in your very helpful picture, and after I changed mine to match yours I now see 0-255 values in the R, G, B settings when using the eyedropper on this grayscale image.
Instead of RGB Color for the First Color Readout I had "Actual Color". This by itself causes percentages to be displayed. All options for the Second Color Readout all seem to produce percentages.
"Actual Color" is what I normally use for the first readout. In the case of a Grayscale document, it will display a K (black) value. For a RGB image, it will display R,G and B values. And so on.
When 8-bit is chosen for the value format, we expect a value of 0..255 to be displayed. As you know, that works fine for the RGB readout, but a Grayscale readout displays a percentage instead.
So if you set one of the readouts to RGB and 8-bit, you can get 0..255 values to be displayed for your Grayscale document.
When the document is Grayscale, the RGB values are a conversion from the document colour space to the RGB working space as defined in Edit > Color Settings. To get the true values of the pixels, the Grayscale document profile and RGB working space must be complementary (for lack of a better word). That's why, in my first reply, I said to use the following combinations:
Doc with sGray profile and RGB working space of sRGB.
Doc with Gray Gamma 2.2 profile and RGB working space of Adobe RGB.

Grayscale to RGB Confusion

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