Adobe Photoshop Training with Dan Margulis

Hi All,

Mike Russel recommended that I post this nagging question I have to this list. I just got Dan’s book yesterday and haven’t started reading except page 125, so please forgive my ignorance. I prepare 100+ product images for a yearly catalog production for the company I work for. Up until now, the printer have done most color correction, but since it’s costly for them to do so, we’d like to perform as much color correction as possible in house. By looking at their printer’s files, I’ve noticed that they manually remove CMY from the cast shadow using Channel Mixer and/or Curves. The printer assures that this is “the correct way” to do so to ensure the consistency thoroughout the catalog.

But Mike told me something different (his quote below):

“If, as you seem to imply, there is a manual procedure involved in creating the drop shadows, perhaps this could be changed.Ê Drop shadows, unlike text, need not be 100 percent K, but just 2/3 or so to keep them reasonably neutral on press.Ê This will be on page 125 of your Margulis book, when it arrives.”

Anyway, the Custom CMYK setting they gave me is SWOP (Coated), Standard 19% Dot Gain 19%, UCR, 96% Black Ink Limit, and TIL 360%. Because the product images are used not only for the brochure but also for other purposes as well (sell sheets, magazines, newspapers, etc.), I don’t want to keep doing something that may not print well with other printers. I contacted them, and they insist it must be done that way to maintain consistency. They also claimed that most sheetfed printers use UCR. They disagree that printing all K cast shadow may be problematic.

So who is right? I need an expert opinion desperately....

TIA

Satoko Mellinger

New to “The” List

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Interesting question. Before I answer, keep something important in mind.

No single CMYK conversion will work for newspapers, magazines, and sell sheets, because the printing conditions are so drastically different. The newspapers have a maximum density of 240, the magazines 280-300, and the sell sheets perhaps 360. I’d recommend keeping the files RGB and converting them using a different profile designed for each condition. The assertion that most sheetfed printers use UCR is interesting; in Photoshop black generation (UCR vs. GCR light) can be hard to differentiate.

As to the shadows... Mike has a point. While most of my drop shadows _onto WHITE backgrounds_ are black only, this is not an absolute necessity. However, if I had to match something printed previously, I’d want black only. Black only drops will not hurt anything, they just require a tight mask.

So I’ll say this - the black only shadows will be most helpful on the newspaper work, less so as the printing increases in quality. But if you know will be masking these images anyway, you may as well keep doing it the same way the printer has been. Deviate only after you feel comfortable with the process.

J

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Satoko

If you want to use the existing shadow I would use the channel mix method, removing the CMY and putting the shape into the k .

Most times we go with a max of 20 to 25% k for Shadows.

These types of shadows look the most natural compared to creating them. There are some 3rd party plug ins, eyecandy I think that has been said to be good.

Dont know for sure never tried it, dans book must have something on Shadows but again never needed it so I havent looked at it.

Black only shadows are easy to control on press, When shifting color around on press the shadows stay neutral.

The only danger is if someone does a profile to profile conversion they

will convert it back to 4/c... Device Links come in handy for this reason.

JR

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Thank u, JR,

I do know how to convert the natural cast shadow to contain only K using Channel Mixer and/or Curves. It’s just that extra work, I was hoping to avoid as I always have to do it in CMYK as my last step after doing everything in RGB. I guess I cannot get around it. Looking at their files, K gets as dark as around 75% right next to the product. I always thought their altered natural cast shadow looks too strong and artificial. I personally prefer around 30%.

One other thing that has been bugging me is they have never matched the logo color although we are paying big bucks for their color correction. So logo colors can be anywhere and can look quite different on page to page and even two products sitting next to each other. That’s one other reason I’m trying to bring more color correction to in-house (=me).

If any of u know used Eyecandy, the 3rd-party plug-in JR mentioned, pls let me know what u think of it. That may ease my pain of manual labor

;)

Satoko

P.S. I’ve leaned it the hard way of K shadow reverted to 4C shadow when I did the profile-to-profile conversion the other day. I was green and didn’t know any better then. I do know now, “never convert one profile CMYK to another.”

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Thank you, J,

I do realize that no single CMYK conversion works: I do prepare files differently for each repurpose from Adobe RGB (1998) oriainals. However, since the brochure project is massive using the most product shots and recurs each year reusing many shots and adding new ones, I do need to know for sure if preparing K only cast shadow is universally accepted practice suitable for other mid- and low-end printing conditions. As u mentioned, u yourself prepare your cast/drop shadows using B only. And yes, these product shots are printed on white backgrounds with the high-end printer who seem to know what they are talking about. They strongly recommend against preparing drop shadows containing any trace of CMY to avoid any hint of color cast. I was also surprised with their firm statement that “mostÊsheetfed printers use UCR” as I thought most sheetfed printers use GCR. I’d like to know if this is true.

Maybe Dan’s Rule Four & Five on page 125-126 don’t apply if the printer uses UCR. Also most of the products are black bags, sometimes with color fabrics, so trapping may be a non-issue. I suppose I have to keep doing it their way.

Satoko

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Well, everyone is!

Putting the shadows only in K solves one problem (consistent neutrals) but it introduces another problem - registration issues. A small amount of neutral CMY can solve this.

I agree with the advice to mix a strong amount of K into the shadow but to also have minor CMY values too, similar to what a Heavy GCR separation would do.

One can get there manually by channel mixing the existing shadow (with luck on a layer by itself) or by combining a heavy gcr shadow into the UCR file.

Stephen Marsh.

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Satoko writes,

These are unusually ambitious settings that will not work well elsewhere. Most printers will not accept work with large areas of extremely heavy ink coverage, and a 360 limit is asking to provoke that problem.

That’s not correct. In theory it doesn’t matter how you construct the drop shadows. In practice, if you make them only out of CMY, and the job is misprinted, there may be an undesirable color shift. Putting a certain amount of black into the drop shadow in preference to CMY is a sensible insurance policy against this danger. Making the shadow *entirely* out of black is cutting the baby’s head off in order to cure its sniffling.

If the drop shadow is entirely black, and the black comes down too heavily that day (not uncommon) the shadow will become too dark, and you will likely see a harsh edge where it ends. Plus, if there is a registration problem, obvious light areas may develop on one side. Also, shadows biased toward blue are usually preferred to those biased toward any other color. Therefore, a useful supplementary insurance policy is to make the shadow with slightly more cyan than would make a gray. This can’t be done effectively if the shadow is all black.

In short, if the job is misprinted, a 0c0m0y40k shadow is probably going to look even worse than a 40c30m30y one; and if the job is printed correctly, then either one will do just fine. But if you set the shadow up as 30c20m20y20k, you get the best of both worlds: you can’t get a harsh edge, there’s limited room for extra darkening, and with so much black it’s nearly impossible to move the overall color off gray.

Dan Margulis

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on 11/24/04 10:09 PM, Satoko Mellinger wrote:

It1s OK but I1d recommend the 3D Shadow Filter from Andromeda software. It1s much more powerful and was recently updated for OSX if you1re using that.

http://www.andromeda.com/

A bit of a learning curve but very powerful!

Andrew Rodney

http://digitaldog.net/

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I've done work for clients who have set up a batch action to doctor their drop shadows. You could set it up any way you want...using the severed baby's head "black only" approach, or Dan's suggestion of 30c,20m,20y,20k. As I recall (bear with me, this was several years ago) we cut very precise paths around the products and always gave the path the same name. The action then used the path as a selection and applied whatever magic/voodoo to the drop shadows was desired. It worked great and everything printed consistently.

Regards,

Eric Bullock

Color Guy

Hecht's/Strawbridge's Advertising

685 N. Glebe Road - 5th Floor

Arlington, VA 22203

703.247.2391

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So u are saying the most sheetfed printers use UCR, not GCR? I'm confused because that's not what I read somewhere else.... But then I've never worked in prepress/printer, so I wouldn't know. Mine is just book knowledge. Can u clarify that for me?

They say printing all K cast shadow does not cause any problem -- "certainly not in our shop". I suspect since they have such a high confidence in their press, they think eliminating color cast problem with all K shadow is critical than the misregiatration problem which they don't even acknowledge. Borrowing Mike's quote, when I told them that cast shadows need not to be 100% K, but 2/3 or so to keep them reasonably neutral, they reply,

"That would be true if you consider 1 picture all by itself on the sheet. However, many images run in-line on the press sheet; including 4/c beauty shots, non-black bags, colored backgrounds etc. As we adjust color for all elements on the sheet, the color of a CMYK drop shadow would also shift from warm to neutral to cool etc. They would not be consistent throughout; if they print black only, you eliminate this potential problem. Can we print CMYK drop shadows? Yes. Do we recommend it? No."

Maybe they have such a different press condition that misregiatration problem is a non-issue for them? I don't know.... All I can say is that their cast shadows look dark and unnatural not all but on some pages though I don't see any obvious banding at the end of the shadows. That's what started my questioning of their all K shadow process.

I hear what u, Mike, and Dan say about the misregiatration issue, and it concerns me that doing all K is not suitable for other printers even if Hemlock insist on it. If we decide not to do all K shadows, I need to make a strong point and present it to my boss as she is no expert on the printing issues either. I can almost see myself preparing two versions of product shots: one with all K and another with CMYK shadows.... But then "Hemlock can fix the drop shadows, for an additional cost as in the past."

I'm sorry, but I'm still in a fog so to speak....

Satoko

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If I understand what you are looking for is a direction and if you are lucky a black and white answer.

I think that you can talk to a lot of sheet fed printers about UCR/GCR and you will find about half the time they don1t know if they use it or not.

My view for sheet fed printing on a good paper is to use as much ink as possible such as 340% or more. But that1s just me after 20 years of making color seps for sheet fed printers without any ink drying problems.

I don1t think anyone on this list can provide a black and white answer. However, your best bet is to call the printer and ask the questions you have asked here about UCR/GCR. If they are a good service provider they will give you the details for the color separations. If they are not that good, then they will say something like "oh it does not matter just use the Photoshop defaults for the color separation" and then we will take care of the file.

Good luck

Jim Rich

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I am certainly no whiz here, however.. two things seem obvious to me..1) the registration.. it costs you nothing to make a non-100%K shadow and will save your hide when the (reality of)registration does become an issue.. and 2)as was stated previously your cmyk black shadow will have such a presence of K that the adjustments these printers discuss As we adjust color for all elements on the sheet, the color of a CMYK drop shadow would also shift from warm to neutral to cool etc. will not appreciably shift unless they make a HUGE (inappropriate)adustment..

and my opinion from their communications indicate that if there were any problems on this job.. they are not going to accept any responsiblity-100K shadows or othersize.. jim bean

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Thank u, Dan. This is great info for me to explain to my boss on pros and cons of cast/drop shadows :) I wonder how many ppl on the list have actually seen this all K shadow misprinting problem materialized.... as a few ppl on the list responded with positive comments about all K shadow....

Satoko

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Thank u, Jim. So I shouldn't be expecting a black-and-white answer, and this is a gray matter to the most regarding UCR/GCR. I did talked to my printer, and I'm just trying to understand my printer's firm statement that most sheetfed printers use UCR as well as their strong stand on K only shadow. I think if the sheetfed printers themselves don't know which they use, then Hemlock (my printer) shouldn't be speaking for other sheetfed printers and claim that most sheetfed printers use UCR. Because Hemlock supplied me with all info about their press setting (Min. Hilite 2%, Max Shadow 98%, Black Ink Limit 96%, TIL 360%, Dot Gain 19%, UCR) plus an ICC proof profile, it led me to believe that they know what they are talking about the UCR/GCR matter and ink treatment of cast shadow as well. So after all, if I take it correctly, even a good printer doesn't know everything.

I appreciated your 2 cents. I think it's getting clearer :)

Satoko

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Satoko

We have been using black only shadows for many years, never seen any registration problems.... ever!

Have run many jobs on Web and Sheetfed, all high quality brochures and catalogs.

I would rather run black only, worst thing that could happen is it would run lighter or darker not really a big deal as what has been said before. Have had supplied jobs that had issues with 4/color shads getting casted, again I didnt set them up but thats what became of them.

If the printer is asking for K only I would give it to them, they know best and you did ask

John R

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Thanx for everyone who responded to my question. After careful considerations, I've decided to supply them with K only files as they ask. For other repurpose I'd ask each printer of their preference and supply them what they prefer. I appreciated the pros and cons of the issue. At least, I have now deeper understanding of what can go wrong with each approach. Thanx again.

Satoko Mellinger