Creating a B&W CMYK tiff with just two colours

[irishgrizzly]

I'm trying to create a black and white photo that will print in four colour, but will only use black and a little cyan to give it depth. I was told to open in photoshop, convert to grayscale, back to CMYK, then have a layer above with a flat colour (100 black 40 Cyan) with the Hue blending mode turned on. Flatten and save. However looking at the values I still have yellow and magenta in there. Anyone know what I'm doing wrong?

Thanks

[jerryrock]

I really don't understand your workflow, but there is an easier way to obtain the same effect. With the original RGB image (I don't know why you work in CMYK), go to image/adjust/black & white and check the tick box for "Tint". Slide the hue slider to obtain a cyan tint and adjust the saturation of the tint.

[Jim Campbell]

I'm trying to create a black and white photo that will print in four colour, but will only use black and a little cyan to give it depth. I was told to open in photoshop, convert to grayscale, back to CMYK, then have a layer above with a flat colour (100 black 40 Cyan) with the Hue blending mode turned on. Flatten and save. However looking at the values I still have yellow and magenta in there. Anyone know what I'm doing wrong?

Thanks

Right. I think I understand ... you're not looking for a cyan tint to a greyscale image, you want the black to be replicated at 40% on the cyan plate, to give what printers like to call a "rich black" ... yes?

I think that the easiest way to achieve this is to leave your image as a greyscale TIFF and create a new colour swatch for "rich black" in InDesign or Quark that's made up of C40M0Y0K100. You can then tint the TIFF on the finished document from within your DTP app of choice, although you will need to check the trap settings of black for the document and ensure that black is set to Overprint and not Knockout.

You'd need to run out separations to make sure that works, BTW.

I was just about to have a go for you when I discovered that InDesign CS3 (v5.0) doesn't appear to work with 10.5.2.

(Something else I'll have to waste time fixing. Not terribly impressed with this Leopard update, so far.)

Cheers!

Jim

[Jim Campbell]

Brought to you from memories of days gone past ...

Open your grayscale document.

Go: Channel -> New Spot Channel -> Colour C40M0Y0K0 and Solidity 100

Copy the contents of your Grey channel and paste into the Cyan channel.

Create a second Spot Channel -> Colour C0M0Y0K100 Solidity 100.

Paste your image into this one too.

Now, delete your Grey channel and Save As -> DCS 2.0 (check the Spot Colours option).

This is the only format I ever found that reliably preserved spot colour information without trying to helpfully split your colours across all four plates.

Note for future reference that this also supports PANTONES if you go Channel Options -> Colour -> Colour Libraries

You may have to experiment with the dialogue that comes up next - I haven't done this in a while. ISTR that the defaults worked OK, but you will still need to output some separations to make sure that it's doing what you want (ie - the proper b/w image on the black plate and a 40% tint of the same on your cyan plate).

I hope that's some help ...

Cheers!

Jim

[killmoms]

I was just about to have a go for you when I discovered that InDesign CS3 (v5.0) doesn't appear to work with 10.5.2.

(Something else I'll have to waste time fixing. Not terribly impressed with this Leopard update, so far.)

Cheers!

Jim

...I use IDCS3 just fine in 10.5.2. Maybe something else is wrong? :confused:

[MechaSpanky]

[snip]

The reason he is working in CMYK is because there is no printer in the world can print RGB. All RGB images are converted into CMYK before they are printed. When you convert images from RGB into CMYK there is a chance that the colors will shift and appear darker and duller than what is intended. Many people work in RGB because many Photoshop filters will only work in RGB mode but they are always aware of the differences between the RGB color spectrum and the CMYK spectrum. The only time CMYK isn't used is if the client decides to use spot colors instead of CMYK. Spot colors still don't use RGB.

irishgrizzly

What you need to do is
1). Take your desired photo and change it from CMYK to Grayscale (keeping a copy of the original as CMYK just in case).
2). Then change the image from Grayscale back to CMYK. Now you should have a CMYK image that looks like it is a grayscale.
3). Next, click on the "Channels" tab and you should see four channels. You will want to click on the Yellow channel and select all and delete. Then do the same for the Magenta channel. This will give you a two color image, consisting of only Cyan and Black.
4). Now if you want to adjust the color, you need to make sure you are working in that colors Channel, not all of the channels.

Normally you don't want to mess around with an images channel but in some cases you have to. I hope this helps.

[Jim Campbell]

...I use IDCS3 just fine in 10.5.2. Maybe something else is wrong? :confused:

Haven't started InDesign up since I updated from 10.4.11. I get as far as the starting up screen and it announces that it's quitting back to the Finder.

The 5.0.3 updater hasn't worked either. Time for a clean reinstall and see what happens, I guess.

Cheers!

Jim

[MacBoobsPro]

Thats a classic thread title! :D

[Jim Campbell]

...I use IDCS3 just fine in 10.5.2. Maybe something else is wrong? :confused:

Nope. Fortunately, I cloned the entire HDD on my Mac before upgrading the OS. I've just booted from the 10.4.11 back-up on my external drive and -- guess what -- InDesign launches and operates just fine.

Boot from the internal, running 10.5.2 and it won't. The only things that have been installed since the back-up was made are Apple's own updates via Software Update.

The exact same story with the laptop.

Once again, I am less than impressed with Leopard thus far.

+EDIT TO ADD+ Hmph. Old news it seems. All have to do is Erase & Install Leopard (and then update it to 10.5.2 again, because the earlier versions don't play nice with my wifi) and then reinstall CS3 again.

So that's another half a day wasted just to get my system to perform the way it did before I started down this upgrade path. Jeez. ++EDIT ENDS++

Bah.

Jim

[jerryrock]

The reason he is working in CMYK is because there is no printer in the world can print RGB. All RGB images are converted into CMYK before they are printed. When you convert images from RGB into CMYK there is a chance that the colors will shift and appear darker and duller than what is intended. Many people work in RGB because many Photoshop filters will only work in RGB mode but they are always aware of the differences between the RGB color spectrum and the CMYK spectrum. The only time CMYK isn't used is if the client decides to use spot colors instead of CMYK. Spot colors still don't use RGB.


I do have a degree in graphic design.

There is no inherent advantage to working in CMYK with Photoshop, there are the disadvantages that you have mentioned. The LCD monitor can not display the full CMYK color gamut. So your argument that the color will be more accurate (less dull) is void. The modern digital press can accurately translate color information from wide gamut RGB to CMYK. There is no need to convert digital photos from RGB to CMYK.

[JasonElise1983]

I do have a degree in graphic design.

There is no inherent advantage to working in CMYK with Photoshop, there are the disadvantages that you have mentioned. The LCD monitor can not display the full CMYK color gamut. So your argument that the color will be more accurate (less dull) is void. The modern digital press can accurately translate color information from wide gamut RGB to CMYK. There is no need to convert digital photos from RGB to CMYK.

I'm going to jump in on this one. Yes MODERN DIGITAL PRESSES can convert rgb to cmyk, but the op did not say he was printing on a modern digital press. He most likely is printing offset since he is trying to control what colors print where so efficiently...offset pressed can not RIP rgb files correctly and the pre-press people will write you hateful emails/post-it notes if you send them rgb images. that's why if you preflight something in InDesign, it give an error if an image is rgb...because that's not the norm. that's like saying you could design a website at 1900 x 1200 pixels wide because that is what modern monitors use. too bad 90+% of the population can't view it. (i know...strange analogy)

-JE

[Jim Campbell]

The LCD monitor can not display the full CMYK color gamut. So your argument that the color will be more accurate (less dull) is void.

Which is why I work with Gamut Warning on. Plus, CMYK display is closer to CMYK output than RGB display is.

The modern digital press can accurately translate color information from wide gamut RGB to CMYK. There is no need to convert digital photos from RGB to CMYK.

I have over ten years' experience in print design that directly contradict that statement. Plus, I have no idea how you think any press is going to be able to accurately translate a simulated 40% Cyan tint in an RGB document into an accurate split for four colour print.

I do have a degree in graphic design.

And how much experience in pre-press production? Because I have a ton of it, and I cannot agree with pretty much any part of your statements ...

Cheers

Jim

[jerryrock]

Which is why I work with Gamut Warning on. Plus, CMYK display is closer to CMYK output than RGB display is.

I have over ten years' experience in print design that directly contradict that statement. Plus, I have no idea how you think any press is going to be able to accurately translate a simulated 40% Cyan tint in an RGB document into an accurate split for four colour print.

And how much experience in pre-press production? Because I have a ton of it, and I cannot agree with pretty much any part of your statements ...

Cheers

Jim

Jim, please read this recent article:

http://www.ppmag.com/reviews/200703_rodneycm.pdf

This is not just my opinion. I am sure you think you have the ultimate answer, but it is always good to be open to new options.

[Jim Campbell]

This is not just my opinion. I am sure you think you have the ultimate answer, but it is always good to be open to new options.


Of course I don't think I have the "ultimate answer", and much of what is in that article is very interesting, but the newer technologies are an edge behind which many, many print operations trail by a variable number of months or years.

In this specific instance, the OP wanted to get a CMYK image that split to two specific plates in specific percentages and did not generate any superfluous coverage on either the magenta or yellow plates.

I will say again, that I do not see how simulating a cyan tint on an RGB image will give the result that the OP said he wanted. Assuming that there is some kind of software voodoo that will magically give a 40% cyan overprint on black from an RGB image with no trap information (which, personally, I doubt), then your advice would have to assume that the OP's printer was using the latest, dog's b*ll*cks software and hardware.

The advice offered by everyone else on this thread centres on getting a good result from pretty much any press. As such, that advice was sound, whereas yours made an assumption that was, potentially, unhelpful to say the least.

Cheers

Jim

[PixelFactory]

While you can send RGB files to a printer, I find that most images will print faded with poor color quality. The article is talking to photographers who just don't work in cmyk.

For the OP. The method i use is this.

1. open the RGB file and duplicate it (Image -> duplicate)
2. Convert the duplicate to greyscale (I prefer to use the Black & White function first).
3. select all and copy the greyscale image and covert to CMYK
4. paste into the black channel and delete all the info in the CMY channels
5. Copy your original file (the one still in color) and paste into the Grayscale (should create a new layer)
6. Change the blending mode to multiply on the new layer
7. Image -> adjustments ->channel mixer on the new layer

At the top you'll see a drop down menu with your channels (CMYK), in the MYK channels, zero everything out, in the Cyan channel you can adjust the sliders to your liking.

it's a little convoluted but it gives great results

[PixelFactory]

I will say again, that I do not see how simulating a cyan tint on an RGB image will give the result that the OP said he wanted. Assuming that there is some kind of software voodoo that will magically give a 40% cyan overprint on black from an RGB image with no trap information (which, personally, I doubt), then your advice would have to assume that the OP's printer was using the latest, dog's b*ll*cks software and hardware.Jim

There is no software that will do what the OP wanted using just an RGB file. The article's audience is photographers who in most cases never use cmyk.

Is CMYK workflow voodoo for the new breed of graphic designers? I've been in the industry for over 15 years and would NEVER send a file in RGB to press. Too many variables for things to go wrong.

[Jim Campbell]

Is CMYK workflow voodoo for the new breed of graphic designers? I've been in the industry for over 15 years and would NEVER send a file in RGB to press. Too many variables for things to go wrong.

Can I ask why you are addressing these remarks to me? I'm just curious, since you seem to be responding to points made by jerryrock ... my own points agree entirely with your own as far as the general incompatibility of CMYK and RGB colour spaces is concerned for the vast majority of printers and presses.

Cheers!

Jim

[PixelFactory]

Can I ask why you are addressing these remarks to me? I'm just curious, since you seem to be responding to points made by jerryrock ... my own points agree entirely with your own as far as the general incompatibility of CMYK and RGB colour spaces is concerned for the vast majority of printers and presses.

Not arguing, just agreeing. :)

[durija]

Why not just make a duotone with black and cyan? Very easy to control the amount of cyan. If you're not used to working with duotones, just be sure to save it as a eps or it won't separate correctly. I think this is by far the simplest way to go.

[IgnatiusTheKing]

I was just about to have a go for you when I discovered that InDesign CS3 (v5.0) doesn't appear to work with 10.5.2.

I use InDesign CS3 daily on two different machines running 10.5.2, without problem.

[Jim Campbell]

I use InDesign CS3 daily on two different machines running 10.5.2, without problem.

*Sigh* Allow me to modify my original statement, then: InDesign CS3 has stopped working on my system since I upgraded to 10.5.2. YMMV.

Cheers!

Jim

[heehee]

*Sigh* Allow me to modify my original statement, then: InDesign CS3 has stopped working on my system since I upgraded to 10.5.2. YMMV.

Cheers!

Jim
Weird, my InDesign CS3 works fine right from when Leopard first introduced, 10.5.0 to 10.5.1 to now 10.5.2.

[IgnatiusTheKing]

*Sigh* Allow me to modify my original statement, then: InDesign CS3 has stopped working on my system since I upgraded to 10.5.2. YMMV.

Cheers!

Jim

Just letting you know that it isn't a bug with Leopard or CS3, but some quirk of your system. Just trying to help...

[MechaSpanky]

jerryrock,

I'm surprised that as a graphic designer you haven't had any problems with your files once they reach the printer. Truth be told the printer converts all of your images from RGB to CMYK and then charges you or your company for doing it. Depending on the type of work you do, RGB to CMYK conversions can make a huge difference.

You said "The LCD monitor can not display the full CMYK color gamut."

Who said anything about what kind of monitor he has? Not everyone uses LCD monitors. Plus, in the end a printer does not print RGB images. The printing process uses CMYK, not RGB.

Yes there are some modern digital presses that can convert RGB images into CMYK but still in the end you have to have a CMYK image so why not do it right from the start. I have never seen a printer who says "we prefer RGB images". Most printers require CMYK images and if you send RGB images, they will charge you an extra fee to convert them to CMYK (which you should have done from the start). Even if the digital press can convert images from RGB to CMYK, most of the time their conversion isn't as good as what can be done in Photoshop.

Jim Campbell,

I completely agree with you. From reading your posts, I can tell that you are someone who has an intimate knowledge of things that many people have no idea about, like creep, impositions, and pagination. So many of the designers today have no clue what happens when their files get to the printer. A truly good designer knows and understands the printing process.

[jerryrock]

Mechaspanky,

The printer I deal with prefers RGB for photos and there is no extra charge for doing so. The machine is a Xerox iGen Digital Press. I send a color proof with my digital file and the conversion is done by the printer. Converting the RGB photo file to CMYK is destructive and you cannot get the detail back once it is gone.

Your CMYK converted file is also being converted again when it reaches the press to comply with their printer icc profile (in the case of digital press). This is why my printer prefers the original RGB photo file.

I am not saying that everything sent to the printer should be RGB, just photo files. I still use CMYK for all my other graphic elements, but use Pantone color matching.

There are several ways to get to and end product and this is all I was trying to point out. I didn't expect to be attacked for my workflow or method. It is what my client and printer prefer and the method that obtains the best color output for my situation.

Jerry

[Jim Campbell]

Just letting you know that it isn't a bug with Leopard or CS3, but some quirk of your system. Just trying to help...

Not just me, apparently.

http://forums.macrumors.com/showthread.php?t=374967

Thankfully, I'm a design hobbyist these days so this isn't going to cost me money in lost work.

It is, however, going to cost me yet more time uninstalling and reinstalling and generally fannying about to simply restore levels of functionality that worked just fine before I installed this chuffing upgrade.

Cheers

Jim

[MechaSpanky]

jerryrock,

Sorry, I jumped to conclusions. Your last post explains your reasons for using a RGB workflow. I didn't know that you were only using it for photos. I was assuming that you were like the thousands of other graphics designers that I have known that are just sloppy. Your last post convinced me that you are not like that and that you are indeed a graphic designer.

I have seen so many designers that are just incredibly lazy. They don't convert RGB images to CMYK, they use GIF files in their layouts and then wonder why they look "jagged", they send CMYK files that are supposed to print 2 color, they don't send the fonts, they don't send all the images, and so many more. I honestly have to say that at least half of the "designers" that I have meet don't even know what bleed is. How can you be a graphic designer and not know what bleed is? I often come across designers who can't tell you the difference between RGB and CMYK, and many can't tell you the difference between vector and raster images.

Anyways, I apologize. I just don't want young impressionable designers to get the wrong idea and think that it is okay to put together a 300 page catalog using nothing but RGB images.

[Kwill]

I do have a degree in graphic design.

There is no inherent advantage to working in CMYK with Photoshop, there are the disadvantages that you have mentioned. The LCD monitor can not display the full CMYK color gamut. So your argument that the color will be more accurate (less dull) is void. The modern digital press can accurately translate color information from wide gamut RGB to CMYK. There is no need to convert digital photos from RGB to CMYK.

:cool: I've been working in prepress for over 30 years. As a designer, do you really want to see a wider gamut than the press is capable of producing? For the original poster, submitting an RGB file and hoping it will print in Black and Cyan is unwise - it won't happen unless the someone at the printing shop follows one of the suggestions already offered such as...

Good: WITH INDESIGN (advantage: easy)

Create custom color with 100k, 40c.
Place grayscale tiff image in InDesign.
With content tool, select image and change to custom color.


Better: WITH PHOTOSHOP ONLY (advantage: more portable; no reliance on InDesign)

Convert RGB to CMYK.
Look at channels offering most detail. In my test, it was cyan.
Copy and paste detailed channel to black.
Clear magenta and yellow channels.
Save as (CMYK) tiff.


Best: PHOTOSHOP DUOTONE (advantage: absolute control over 2nd color midtone)

Convert image mode to Duotone.
Select "Duotone" from the menu in the subsequent dialog box.
Click on the second square and select a Pantone color similar to cyan.
Name the second color "cyan".
Click on the curve and drag its center down. Refine curve for specific image.
Save image as Photoshop EPS (with screening and transfer function options disabled).


Some print shops have an RGB workflow - meaning they convert RGB images to CMYK using custom ICC profiles before printing. If you obtain such profiles, it can be done before sending to the printer. This allows you to view the channels and see the results (assuming your monitor is calibrated). As far as throwing away data, you can always save an RGB original. Likely the image used in the document will be scaled to a specific size, resolution and cropping anyway. None of this is any consequence, anyway because, as already indicated, an RGB file will not work for the original question posted.

P.S. The highly respected David Blatner is begins by discussing (http://www.ppmag.com/reviews/200703_rodneycm.pdf) formats photographers should save or deliver files. No one is disputing that RGB holds more color information and therefore is the preferred format for archiving originals. He then ends by suggesting submission of sRGB documents to printers. I respectfully, disagree. This particular RGB format is common in digital cameras and Web pages because it has vibrancy meant for computer displays. Adobe RGB (1998) has an even wider gamut and is often preferred by many professionals and recommended by Adobe. There are, however, other RGB formats - without even getting into 8-bit vs 16-bit color.

U.S. Web SWOP is for magazines. Typically, most CMYK printing jobs are sheetfed. If an ICC profile is not available from the printer, reasonably good results can be obtained by using a profile that describes the actual printing process. If you use one printing company that prefers RGB, more power to you!

Regarding the statement: "The modern digital press can accurately translate color information from wide gamut RGB to CMYK," it has not been established that the project in question is to be printed digitally. If a digital print is all that is required, a tinted RGB could be printed on a desktop printer. Here, I have a 12-color 44" digital printer that has a much wider gamut than my 4-color digital laser printer. The former prefers RGB because of so many inks but does well with CMYK. (Actually, all color images are converted to LAB and then RGB internally based on profile within the printer.) The laser printer has more predictable results with CMYK. Offset printing with ink typically uses 4 colors unless it is a special press for 6 or 8 colors, allowing for additional spot color and varnish.

[Kwill]

Controlling midtones becomes significant when overprinting two colors because light tints are darkened and darker shades may plug up. This is one reason why the second ink color is a not 100 percent.

Best: PHOTOSHOP DUOTONE (advantage: absolute control over 2nd color midtone)

Convert image mode to Duotone.
Select "Duotone" from the menu in the subsequent dialog box.
Click on the second square and select a Pantone color similar to cyan.
Name the second color "cyan".
Click on the curve and drag its center down. Refine curve for specific image.
Save image as Photoshop EPS (with screening and transfer function options disabled).



Before closing the Duotone Options dialog, press the Overprint Colors dialog and make certain the black is 0c, 0m, 0y, 100k.

Screenshot provided...

[durija]

I was beginning to wonder if I was the only one who saw duotone as the obvious/simplest solution. Channels....DCS...those are the hard way. Duotones are simple and flexible.