Converting from RGB to CMYK alters shadows

When working with our product photos, I keep them in RGB and add drop shadows to them by drawing rectangular marquees on a separate layer, fill them with black and then apply gaussian and motin blur to them. Works quite well. Plus with the shadow on it's own layer, I can turn it off in InDesign if need be. The problem is when I convert the photo to CMYK for offset printing. It's asks if I want merge the layers to which I say no since I want to be able to turn the shadows off if need be, but when I say no, then the shadows get bigger and do not look as good as they did in RGB. If I say yes to merge, then the shadows look the same as they did in RGB but I lose the ability to turn them off in InDesign.
Is there a way to keep the shadows looking the same when converted to CMYK without having to merge the layers? Using PS CS6 64 bit. Thanks.

gator soup wrote:
... i would think any conversion would be subject to the same anomaly that Photoshop is showing
but i don't know... maybe convert to the destination cmyk before setting any layer effects or adjustment layers
Effects, like gradients, drop shadows, etc are not converted by the color management pixel by pixel because Photoshop doesn't see them as pixels but as a procedure (formula) with key colors for generating the effect in the destination color space. So, for drop shadow, only the shadow color is converted to its closest match in the destination color space but all other parameters affecting the color like the blending mode, opacity, etc are applied in the destination color space which gives different appearance - first, because color space characteristics like gamma curve is different and second in case of a different model (CMYK), the blending of colors is based on entirely different algorithms.
So, basically effects is best to be recreated in the destination color space or flattened before conversion.

Similar Messages

Convert from RGB to CMYK

I've been trying to find solutions to convert images/pdf's from RGB to CMYK. I've noticed that it's definitely possible to convert from CMYK to RGB, but haven't been able to do the reverse.
Does anyone know of a method or a reference that might help me along?
Thanks!

Ugh, I'm a newb and did a better search and found other previous posters asking the same question.
Feel free to close this thread (if you do such things here).

Converting from RGB to CMYK makes the image dull. How do I fix?

I have an image that has a really bright vibrant blue in it. When I convert it from RGB to CMYK, it gets pretty dull. Is there a "trick" or something to do to a file after converting to CMYK to bring back some of it's vibrancy?

Sharingene wrote:
Question on workflow... so do I convert my sRGB to CMYK, work to fix different color issues using some of the methods above, then what? Where does the printer's profile come into play during all of this? UPrint told me for offset printing they use US Web-coated SWOP v.2. Just not sure what to do with this information
Whenever you convert, you're always converting from the source color space to the destination color space.
In this case, your source color space is sRGB, because that's the color space your file is in.
Your printer told you that the CMYK profile they use is USWebCoatedSWOPv2, so that's the destination color space you want to convert to. You can consider that the printer's profile.
So, how to convert?
There are two ways.
First, you could go to Image > Mode > CMYK. Easy, but maybe not right.
That method will convert to whatever defaults are set in Photoshop's Color Settings (Edit > Color Settings). Check out your Color Settings. If they are set to any of the North America presets, you're in good shape, because the CMYK default is USWebCoatedSWOPv2. However, let's say that the printer told you to use Web Coated SWOP 2006 Grade 3. Then you need to take a different approach...
Second way: go to Edit > Convert to Profile...
In the dialog that appears, click on the Destination pop-up and scroll to find the appropriate profile.
Click OK. Conversion done.
This is a more deliberate method that also gives you control over Rendering Intent. (That's another discussion. For now, use Relative.)
-I guess it's used in soft proofing but sure how all this works. If I soft proof and it's still not looking right, am I able to edit with their profile turned on some how?
A soft proof is an on-screen simulation of what your color will look like once you do the conversion. In your case, you would turn on soft-proof (command-Y) while still in sRGB to simulate the look of the CMYK color space.
To select the color space to simulate, go to View > Proof Setup.
Click on Custom...
Click on the Device to Simulate popup.
Scroll to find the destination color space.
Then when you hit command-Y, you'll see a soft proof of that color space.
Best practices suggest that you do the bulk of your color correction while still in RGB, but with soft proof on.
Also, should I get a profile for the paper I'm using as well?
That's what the printer's profile is.
Although I've read somewhere it's hard to have your monitor replicate paper because monitors are so bright....
Not exactly. The challenge in getting a visual match between monitor and proof/print is based on the fact that a monitor is emissive (i.e., it's a light source) and a print is reflective (i.e., it only reflects light that's hitting it.) However, in a proper, well controlled editing environment, it's possible to get a shockingly close match between monitor and proof/print. All the variables are controllable.
The bottom line with all of this is to be able to get accurate, predictable color on press (or out of your inkjet) based on what you see on screen. It can be done; I do it every day. It just takes some study and rigorous process control.
I humbly suggest that you check out my book.
Good luck!
HTH,
Rick
Rick McCleary
author, CMYK 2.0: A Cooperative Workflow for Photographers, Designers, and Printers
Peachpit Press

Color turns Grayscale when converted from RGB to CMYK?!

I have a complex pattern, that looks brilliant with a color layer. However, it was originally created RGB.
I converted the color to CMYK for print, and all the color disappears! Not that the layer is deleted, but the color layer appears Grayscale. The only area where color shows up are in the pieces that are at 50% transparency (see purple diamond). I have all my color areas set to CMYK including the color pallet.
The color will show if I set the layer to multiply, but it doesn't look the same way as it does when its in RGB mode.
I've never come across this before, any help would be greatly appreciated! THANKS!

If I do this, it turns it into an image and it loses its clipping path?

Automatically convert from RGB to CMYK color mode

I have over 900 barcodes provided in EPS format. When I open them in illustrator, they are coming in as an RGB color space file. I need them gray scale solid black in CMYK color mode. I can batch using actions to convert the artwork using "Edit Colors > Convert to Grayscale". However, the document color mode remains RGB. It appears, even after using "Convert to Grayscale", that the RGB color mode goofs up the placed .ai file in InDesign, treating it as RGB and seeing it as a mix of CMYK rather than the 100% black only it needs to be for proper sharp printing.
The actions pallet doesn't record converting the document color mode. Is there a way to automate that file conversion so they are all saved as CMYK rather than RGB, or am I stuck opening each of the 900+ files manually?

While recording the action, from the popup menu in the Actions Panel choose Insert Menu Item, then from the main menu choose File > Document Color Mode > CMYK color.

Converting from RGB to CMYK

A client gave me a PNG made in Fireworks, and I need to pretty much convert this over to a CMYK file that I can send to a printer. SOme pointers would be greatly appreciated...

This is not possible in Elements. You would need the full version of Photoshop to do this.
Colin.

How can I convert Pdf from RGB to CMYK, keeping font color 100% K while working in Illustrator?

How can I convert Pdf from RGB to CMYK, keeping font color 100% K while working in Illustrator?
When I try to open the document in Illustrator and I convert to CMYK the black font converts to rich black, but to set up for Offset printintg I need the text to be only in Black (100%K).
The original source of the document is a Microsoft Word file, I have converted the Word file to Pdf in order to setup for OFfset Printing.
Thanks

I have tried that way, but the downside is that the fonts are set in gray not in a 100%K, also I have to deal with other fonts that are composites and meant to stay Full Color. I could select text by text and convert to gray but, its a 64 page document and I wouldn't want to make a expensive mistake.

How can i convert my file from RGB to CMYK?

I need to convert my pages project from RGB to CMYK. How can I do this?

Which version of Pages and can you be more specific about what file you have and what you are intending to do with it?
Peter

Convert image from RGB to CMYK and back to RGB

Hey.
I wonder if anyone has experience with converting image from RGB to CMYK and back to RGB?
I had a TIF in RGB then converted to CMYK but I figured that it might be better to keep in RGB, so I converted back. I read that it supposed to cause some loss in the data, but I can't see anything on the image, it is still very huge and the 2 RGB files has the same size as well. Is there a way to compare the resolution of 2 images somehow, or how can I see what I lost through the 2 conversions?
Thanks for help

I had a TIF in RGB then converted to CMYK but I figured that it might be better to keep in RGB, so I converted back.
The original RGB data is not being restored by converting from the CMYK version, so the term "keep" seems inappropriate.
What are the actual Color Spaces (ICC profiles) involved?
Is there a way to compare the resolution of 2 images somehow, or how can I see what I lost through the 2 conversions?
How did resolution come into this?
To determine how large a portion of the image has been changed you could
• make a flattened copy of the original image
• place a flattened copy of the RGB->CMYK->RGB image on top of that and set it to Blend Mode Difference
• add an Adjustment Layer (Curves for example) to brighten the image

How do I find out if a photo in iPhoto is RGB or CMYK color? How do I change from RGB to CMYK?

How do I find out if a photo in iPhoto is RGB or CMYK color? How do I change from RGB to CMYK?

Open the file with Preview, type Command + i to bring up the Info pane and it's color mode and profile will be listed as shown here:
To change the color mode to CMYK you'll need a 3rd party image editor like Photoshotp or GraphicConverter to do it. Why do you need CMYK?
OT

Can I use either PE9 or LR4 to convert Adobe RGB to CMYK?

Can I use either PE9 or LR4 to convert Adobe RGB to CMYK?

LR4 does not convert to CMYK. You would need CS6. But if your requirement is a one-off you may be able to get your print lab to do the conversion at a reasonable price.

When printing a photobook does Apple convert the images from RGB to CMYK?

I'm a little confused by Apple's Photobooks. Most printers require all images to be in the CMYK colourspace, since the inks used are always CMYK. Yet Apple requires Photobook images to be jpegs in the RGB colourspace. Does this mean Apple's printers (presumably plural, since they are all over the world) do some sort of autoconversion RGB to CMYK? Surely this would result in a major downgrading of quality? I've seen a few non-Apple photobooks printed with unconverted RGB images, and they look dreadful - overblown red and yellows, with awful colour casts. I've not seen an Apple Photobook myself, presumably the colours are realistic?
Comments anyone?

Quote from the Reference:
Linear Light
Burns or dodges the colors by decreasing or increasing the brightness, depending on the blend color. If the blend color (light source) is lighter than 50% gray, the image is lightened by increasing the brightness. If the blend color is darker than 50% gray, the image is darkened by decreasing the brightness.
Now consider the values that a neutral medium grey would have in the RGB and the CMYK spaces you use.

Conversion from RGB to CMYK

Hi,
I would be so grateful if someone could help! I need to submit a PDF of a book I have written to the printers. They tell me that they are printing in CMYK. My book has many paintings inside and two use RGB mode (others are CMYK). I have tried converting these to CMYK however they loose their colour variations and brightness. It is important that the colours remain the same. Is it necessary that I convert these to CMYK (my printer said he would try printing samples of the PDF's I've sent in RGB mode and see what happens). I am worried since when I export the book to PDF I get a big exclamation mark warning me not to proceed since all is not in CMYK. Is this simply a caution or is there any reason for real concern. Help!
Thank you, Rachel

There's no way to tell what the settings are from what you've posted. This is a modification of the [High Quality Print] predefined preset, which DOES NOT convert colors to CMYK, but without going through the panels there's no way to know what was modified.
Whatever settings you end up using, you must look at the "output" panel and check what it says under color. If you are expecting the output to convert RGB to CMYK you must set that field to one of the "Convert to Destination" settings, and under destination you must choose the correct profile for your printer conditions.
Choosing "Convert to Destination" and a profile that doesn't match your document CMYK working space will result in the appearance of colors being preserved, but all of your native CMYK elements, including your black type, will be converted tot he new color space, and more than likely your type will now be a four-color rich black instead of K only, which is a printer's nightmare.
Choosing "Convert to Destination (Preserve Numbers)" will keep the CMYK values for native elements, which will preserve your solid blacks, but will result in some color shifting as the numbers are re-interpreted in the new space. This is roughly equivalent creating a document in one working space, then ASSIGNING a new working space before export.
Peter

Conversion formulas from RGB to CMYK

Hi,
I've been writing a Colour swatch tool (in excel! hell yeah!) which allows me to pick a bunch of colours, generate complimentary colours from them, blend between 2 colours in a set number of steps and a whole bunch of other cool stuff, and then output this as a photoshop or illustrator swatch file.
As part of this tool I want to be able to covert the rgb values to cmyk. There is very little information on this on the web and what there is is fairly inaccurate.
For example,
RGB:50,128,128
Converts to CMYK 61,0,0,50 (%) using the formula found at easyrgb.com (this formula is the most prevalent one on the web/web forums)
Photoshop converts these RGB values as CMYK: 80,33,48,8 (%)
While these two colour values are *similar* the ones generated by the easyrgb formulas are nowhere near the photoshop values.
See? stupid useless formulas. (I am aware of the differences and overlap of the two gamuts)
Whilst I know that the conversion done in photoshop is done using ICC templates, and that often these conversions are device dependant, there must be a more realiable way of converting from one colour space to another using good old reliable cold hard maths.
Does anyone know what that might be? you guys at Adobe: I AM LOOKING AT YOU.
Hope you guys can help,
~silvery~
For reference I have included and commented the easyrgb formulas:
First: RGB -> CMY
C = 1 - ( R / 255 )
M = 1 - ( G / 255 )
Y = 1 - ( B / 255 )
Second: CMY -> CMYK
var_K = 1
Initally sets var_K as 1, although this is dependant on variables below
if ( C < var_K )   var_K = C
if ( M < var_K )   var_K = M
if ( Y < var_K )   var_K = Y
This bit finds the smallest value from the CMY range and sets this value as var_K
if ( var_K == 1 ) { //Black
    C = 0
    M = 0
    Y = 0
If var_K (the value that K is calculated from) is 1, then all the CMY values are reset to 0
else {
    C = ( C - var_K ) / ( 1 - var_K )
    M = ( M - var_K ) / ( 1 - var_K )
    Y = ( Y - var_K ) / ( 1 - var_K )
If the value of var_K is anything other than 1 then use the smallest value from the CMY range
K = var_K
The value of K as filtered out from the conditions above

Oliver,
I'm not sure what you mean by the term 'meta' color profiles, but I'll take a stab at what I "think" you are asking. There are some fairly widely accepted "standards" out there for both RGB and CMYK.
In the RGB world, for example, sRGB, Adobe RGB (and to some extent, ProPhoto RGB) have a fairly wide following. These are all ICC profiles, which nail down the boundaries of the color gamut and the definitions of any tri-stimulus combination of red, green and blue. Basically, they are matrix profiles that establish the positions of the Red, Green and Blue primaries, and these positions define the outer limits, or color gamut, of the color space. sRGB is a relatively small color space, so some viewable and printable colors get clipped (sRGB is the general internet, email standard and is widely assumed for many non-color managed appplications, printers, etc). sRGB can handle a fairly wide range of colors, but does clip some colors in brightly colored originals. It has the advantage of being the most widely adopted standard, plus the steps between colors are very close together. I use sRGB for average images, most people pictures, etc. Adobe RGB spreads the primaries further apart, so it describes a wider color gamut. Because the primaries are further apart, the steps are slightly larger from one color to the next, but marginally so. I use Adobe RGB for most of my brightly colored images that will get clipped in sRGB. Adobe RGB is also generally a good choice for images that will ultimately go to a printing press or inkjet. ProPhoto RGB pushes the primaries WAY apart, so it describes a HUGE color gamut...in fact, many of the colors that can be defined in ProPhoto fall outside human vision, and certainly monitors and printers.Due to the wide spacing of steps in ProPhoto RGB, images should be worked in in 16 bit, otherwide you may see some banding and posterization if large edits are made.
In the CMYK world, certain "standards" have been established, mainly for commercial offset printers (both web and sheetfed presses). By creating a standard, they are trying to establish the ink limit, densities, color gamut, dynamic range, gray balance, etc, of a "generic" sheet of commercial printing paper on the average well-maintained press using standard ISO inks, using good process control, mesurements, etc. By it's nature, this process has to encompass a wide cross section of presses, so it may act as a limitation on what some modern presses are capable of, but that's what standards usually do. If a good printer, with a modern press and great process control decides to sidestep the standard, they can probably extend color gamut, dynamic range, etc, but at the cost of no longer being "standardized". If commercial printers are "truly" trying to meet the standard, they will run tests, take measurements, and adjust their entire workflow so it matches the standard, within acceptable tolerances. Lots of shops "claim" to adhere to SWOP or GRACoL standards, but the majority of them don't. Standards for presses make some sense, because blending CMYK inks together (especially if they use ISO standard inks) on paper usually has a reasonably narrow range that works, though the paper makes a huge difference. (the same cannot be said for inkjets, monitors and many other processes, so they generally do not have standards). So for presses, there are standards for matte and coated papers, web presses, sheetfed presses, newsprint, etc. Each of these standards has its own ICC profile (or a family of profiles) that establishes ink limits, color gamuts, etc.
All ICC profiles have the necessary tags and data to comply with the ICC specification. One of those requirements is a "profile connection space", which is usually L*a*b* or a variant. So, an file on your computer may be tagged as an Adobe RGB file, and if you wish to prepare it for a sheetfed press using glossy stock, you could convert the file to GRACoL2006_Coated1v2.ICC (an industry standard profile for No. 1 coated stock on a sheetfed press). Since both files have the ability to "speak Lab" a translation can be made from one color space to the other. The numbers in the Adobe RGB file will be converted to L*a*b* (the universal translator), and then the L*a*b* numbers will be converted to CMYK, specifically GRACoL2006_Coated1v2.ICC. So, now you have a file in CMYK space with new numbers. It is worth noting that RGB has only three colorants to define colors, but CMYK has four. So, while in RGB there is only one way to define a specific color, in CMYK, there are many possible combinations that can generate many colors. This adds complexity to the equation. The CMY colors are called subtractive primaries, and are opposites of RGB (additive primaries). The "K" (black ink) is added for text, line art, neutrality, extra Dmax, and because the CMY inks are not pure and don't deliver a true black all by themselves. If the inks and paper were perfect, you could theoretically get away with CMY all by themselves, except for registration issues, text, line art, etc. Also, the additional "K" ink can help reduce the total ink limit, save ink, reduce costs, and improve quality.
Sorry for the book. This is not a simple subject, and we have only touched the surface.
Lou

Specific Colour changing Script from RGB to CMYK

I need to change the RGB values (imported from word) to specific CMYK values in Indesign (its not a straight swop) so I need a script or a similar plug-in that enables me to input the colour values for the CMYK so they automatically change.... the doc i work on is huge and im importing from a word file many times so i need to save time!!
Can anyone help me?
Thank you!

Hi Phil... Hmmm not sure if i explained myself! Or maybe I am being thick.... I tried the new code but im not sure I was clear on my problem?
This is the current code i use to change the RGN values to the CMYK is: I have entered the RGB and CMYK values as they need to be changed and it works but the swatch pallette ends up looking messy! See below.
var myIDOc = app.activeDocument;
var mySwatch = myIDOc.swatches;
for (var j=4; j<mySwatch.length; j++){
    try{
         if(mySwatch[j].space ==ColorSpace.RGB){
             if(mySwatch[j].name=="Word_R122_G75_B153"){// may be this is correct you can check the indesign swatches name
                 mySwatch[j].model=ColorModel.PROCESS;
                 mySwatch[j].space = ColorSpace.CMYK;
                 var myCV = mySwatch[j].colorValue=[48,72,0,0];
                 mySwatch[j].name = "C=" + myCV[48] + " M=" + myCV[72] +" Y=" + myCV[0] + " K=" + myCV[0];
         }catch(e){alert(e)}
var myIDOc = app.activeDocument;
var mySwatch = myIDOc.swatches;
for (var j=4; j<mySwatch.length; j++){
    try{
         if(mySwatch[j].space ==ColorSpace.RGB){
             if(mySwatch[j].name=="Word_R255_G0_B255"){// may be this is correct you can check the indesign swatches name
                 mySwatch[j].model=ColorModel.PROCESS;
                 mySwatch[j].space = ColorSpace.CMYK;
                 var myCV = mySwatch[j].colorValue=[0,100,0,0];
                 mySwatch[j].name = "C=" + myCV[0] + " M=" + myCV[100] +" Y=" + myCV[0] + " K=" + myCV[0];
         }catch(e){alert(e)}
var myIDOc = app.activeDocument;
var mySwatch = myIDOc.swatches;
for (var j=4; j<mySwatch.length; j++){
    try{
         if(mySwatch[j].space ==ColorSpace.RGB){
             if(mySwatch[j].name=="Word_R0_G0_B255"){// may be this is correct you can check the indesign swatches name
                 mySwatch[j].model=ColorModel.PROCESS;
                 mySwatch[j].space = ColorSpace.CMYK;
                 var myCV = mySwatch[j].colorValue=[100,0,0,0];
                 mySwatch[j].name = "C=" + myCV[100] + " M=" + myCV[0] +" Y=" + myCV[0] + " K=" + myCV[0];
         }catch(e){alert(e)}
var myIDOc = app.activeDocument;
var mySwatch = myIDOc.swatches;
for (var j=4; j<mySwatch.length; j++){
    try{
         if(mySwatch[j].space ==ColorSpace.RGB){
             if(mySwatch[j].name=="Word_R255_G255_B255"){// may be this is correct you can check the indesign swatches name
                 mySwatch[j].model=ColorModel.PROCESS;
                 mySwatch[j].space = ColorSpace.CMYK;
                 var myCV = mySwatch[j].colorValue=[0,0,0,0];
                 mySwatch[j].name = "C=" + myCV[0] + " M=" + myCV[0] +" Y=" + myCV[0] + " K=" + myCV[0];
         }catch(e){alert(e)}
var myIDOc = app.activeDocument;
var mySwatch = myIDOc.swatches;
for (var j=4; j<mySwatch.length; j++){
    try{
         if(mySwatch[j].space ==ColorSpace.RGB){
             if(mySwatch[j].name=="Word_R0_G0_B0"){// may be this is correct you can check the indesign swatches name
                 mySwatch[j].model=ColorModel.PROCESS;
                 mySwatch[j].space = ColorSpace.CMYK;
                 var myCV = mySwatch[j].colorValue=[0,0,0,100];
                 mySwatch[j].name = "C=" + myCV[0] + " M=" + myCV[100] +" Y=" + myCV[0] + " K=" + myCV[100];
         }catch(e){alert(e)}
var myIDOc = app.activeDocument;
var mySwatch = myIDOc.swatches;
for (var j=4; j<mySwatch.length; j++){
    try{
         if(mySwatch[j].space ==ColorSpace.RGB){
             if(mySwatch[j].name=="Word_R234_G229_B255"){// may be this is correct you can check the indesign swatches name
                 mySwatch[j].model=ColorModel.PROCESS;
                 mySwatch[j].space = ColorSpace.CMYK;
                 var myCV = mySwatch[j].colorValue=[8,10,0,0];
                 mySwatch[j].name = "C=" + myCV[8] + " M=" + myCV[10] +" Y=" + myCV[0] + " K=" + myCV[0];
         }catch(e){alert(e)}
The outcome is the swatch pallette attached:
How do I incorporate the new code to make sure all the values are hopefully to end up looking similar to this!!??
Thanks for all your time and effort helping me!
babeanz

Converting from RGB to CMYK alters shadows

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