Printing grayscale images in CMYK?

Asterix

New member
Hello.

Is there any advantage in converting grayscales to CMYK?

One senior designer at a place I'm currently working rants hysterically that by converting to CMYK you get a deeper 'richness' in the final image, but I'm thinking all you get is muddy looking blacks.

We're printing on uncoated stock with a 20% dot gain. Things aren't helped much by the quality of the 'grayscales' which invariably come over as RGB files at a less than desireable dpi for their intended output.

I'm just wondering whether there's any advantage to going this route at all...

Many thanks in advance.
 
My experience is that it can make a significant difference. The problem is that it's tricky to get the curves right. And when you are on uncoated stock is even worse. Then you have to know that the grey balance is pretty under control in the printing process.

If you have the time to do some iterations on getting it right, AND are pretty confident that the actually printing process is stable, my experience is that it can make a huge difference. If not, you'll be going down a worm hole. Been there, done that. It's not pretty.
 
This is a popular view among designers, especially those "seniors". This is completely based on individual opinions and NOT a fact. Grayscale images printed 4C tend to have a warm color look, some interprets this as "richer".

I'm an advocate if you want richer grayscale, instead of printing as 4C images, convert your images to duotone to bring out better tonality in your grayscale images. Be sure to adjust color curve to find the correct balance and save file in EPS.

Of course, if your entire project is 4C and some "senior" insist on printing as 4C, I would probably let them have what they want and not waste time educating them or do the work for them.
 
Guilty as charged. I am a senior.

I aqree that duotones or even quad tones with four different blacks is the optimal way to go. Problem is that it's become pretty hard to find two color or 4 color black printing processes. A couple of years ago I did a tri tone with stochastic screening that was awesome.

It also depends on what the output engine is. I've had amazing results on the Igen because the black toner has an amazing density. Single color black is definitely the way to go. Don't have any experience with other digital devices.

Using 4c offset that is not under grey balance control, or if you don't have the time to get the curves right, I also agree that it's not worth the trouble.

I wouldn't just give them what they want. Cause when it comes out yucky, they are going to blame you anyway. Might as well try to explain the downside up front.

All depends on the customer, the job and what is going to work for them.

Just the two cents of this " senior"
 
It is a shame that there isn't the alternative to choose what GCR to use on a per image basis. Greyscales can look really good with an above average GCR. filling in the spaces on the middtones gives a softer, smoother image especially in portraits. The trick is to keep the bulk of the grey scale in K so that variations are minimal. We just did a 5 colour print run with CMYK+K, it was mainly to have a nice rich black backround without getting too much ink. first K at 80% second at 100% I love trapping for neg text :D
 
No GCR adjustments available for the designer/prepress operator in the design software. Features that involve hacking the output files don't count ;)
 
Thanks for your helpful replies.

I've been looking at Blatner & Fraser's take on this and although they don't address it directly they do offer some advice which would be:
a/ Make all initial tonal adjustments in RGB before going to greyscale, then
b/copy the black plate and paste it into a new CMYK file duplicating it for each channel, then
c/ Apply curves to the CMY channels

This kinda makes sense as converting directly via the Mode option loses information by stretching the pixal content so, I believe, you lose detail in the midtones.

Duo's, Tri's, or Quadtones would certainly be an option too.

I'm more concerned that in 'their' hands they're more likely just to click on the 'Mode' button and lose alot of info in the first step...
 
When I was teaching production to designers, we were pushing them to work in RGB mode for images. Stay away from the mode button. Give your printer RGB. The big problem was that almost every printer the students talked said they required CMYK files...:)
 
Sure... because all capture devices, displays etc work within an RGB gamut... but I'd never supply artwork for print with RGB files – my printers would redicule me for starters!

The real problem occurs when you make that switch to CMYK, and there's been reams written about that... and yeah, you're right, it's never as simple as just flicking the 'mode' button.
 
That's exactly why designers should Not Try to Do This at Home. I fear the real underlying problem is the conventional wisdom of printing companies. In my humble opinion, it's driven by the fear of screwing something up. Better to produce "good enough"stuff...as long as they don't have the responsibility for making the conversion. It does make sense. But it sure does make life much more complicated.
And thus . . . fear (of disappointing a customer) make cowards of us all. :)
 
I agree...

and it's compounded by the timescales we all have to work by. Schedules always get squeezed at the Marketeers end, leaving less time to proof at the critical print stage.

TBH I blame those Marketing Departments, who, in my opinion, have destroyed design in this country [the UK] and put everyone under greater pressures. I was always taught [at degree level] to work closely [and respect] my printers, but with time being squeezed out the margins it just gets tighter & tighter.... and the last person in the chain: the printers... suffer most.

I think this is also compounded by the technology we're using, which makes secretaries from Hull believe they have expert design & repro skills for print – everyone thinks they can do what is essentially very skilled work. The mac's a great tool and the software Adobe have created is superb, don't get me wrong, but it seems to have swept away alot of critical skills and compressed work schedules to working on the fly – everybody wants polished work immediately.
 
I also agree. I'm not sure I would blame marketing departments though. They don't have any time to think either. They're frightened by whoever is the next up in the food chain. They lord it over printers cause they have a hard time getting respect from their bosses.

Anyway, that's why I've been fighting for the RGB workflow. The only thing they have to do is KEEP IT IN RGB. If your software doesn't do that, get new software. Given that they capture their images in digital camera's or steal them from the web, this is really a case of less is much,much more.

As for the decline of design I have a different take. I think between 70 to 85" design ever produced was pretty mundane. Consider Victorian typgraphy. It's just confusing because mostly only the good stuff survived. The problem now is that mostly the pie is so much larger.
 
4-colour mono photos are fantastic, if you do it safely. The trick is to set up a profile with 100K, and no more than 20 or 30 of CMY.

Here's a thread where I explained it recently: RGB & CMYK - Canon Digital Photography Forums

My audience were photographers, so I dumbed it down a fair bit, but the principles are clear. The risk of cast is negligible.
 
If Monochrome black is your final decision, try this. Convert Grayscale file in Lab, adjust contrats and levels if needed, copy L channel in K channel of an empty CMYK file. Much better than grayscale.
 
We create 4/C black & white all the time. It really is a richer black than just a black channel alone. I agree that quads and duos using just black and gray inks will give the ultimate reproduction quality, but most of our images end up as ads in regular SWOP pubs, so if we want a rich black and full tonal range 4C is the way to go.

As everybody has said, you've got to get the curves right and it is very tricky. The black channel should lead the whole way, with the other channels not starting significantly until black is up around 25%. There are lots of ways to build them, including Asterix's method of pasting channels. Another way is to use the duotone function of photoshop, create a quadtone with your 4 colors and control the individual channel curves there. We use a custom built profile based on the GRACoL2006_coated1 data set, but it requires a little tweaking once in CMYK.

-Todd Shirley
 
In the past I have used the preset Quadtone supplied with Photoshop with great results albiet on coated stock. Look in the photoshop application folder, presets, duotone, quadtone, process quadtones, CMYK Neutral.

I made my image grayscale, balanced and adjusted as necessary. Then just applied the quadtone (click Load in the duotone dialog) preset and saved. Printed great.
 
The irony of this thread is I actually have a production person telling me the same thing today and request all grayscale be converted to 4C. Got into a heated argument trying to educate this person on the work require to make 4C grayscale correct with curves and not just a simple color mode conversion.

BTW, the reasoning for 4c-grayscale is because the product is whatelse–4C. According to her, there is NO reason to print in grayscales. It's just not worth my time explaining this stuff anymore. No one listens–anyone.
 
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Well, grayscales look pretty weak if they're sitting on a page full of colour images - the dmax is visibly weaker. I always print 4-col monos where possible.
 

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