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  • Request for specifications

    I can't seem to get a clear answer from the printer so I thought someone here might be able to help. We have a job being printed on a Heidelberg CD 74 F format and I am looking for an estimation of maximum shadow density and lowest printable highlight value. Also, would US Sheetfed coated v2 be the best profile to use? Any other suggestions would be appreciated because when I asked the prepress manager what the least printable highlight value was, his answer was "300DPI." At that point I pretty much knew there was no point in asking any more questions.

  • #2
    Re: Request for specifications

    Hi there,

    are you asking what the lightest tint is and what the biggest tint is before it becomes filled in and 100%. e.g will a 1 % on plate become a 3% when printed and at what point will a 100% happen. my guess is 2% low end and about 90-92 high end. only guesses though and the latter is dependent on many factors. I run SM 74s and im sure i could get these values on coated stock.

    Edited by: Paul Green on Jan 19, 2008 2:16 PM

    Edited by: Paul Green on Jan 19, 2008 2:19 PM

    Comment


    • #3
      Re: Request for specifications

      I am sure you know that reproduction of images is about using the correct profile that is designed to print to the same standrd they were designed for.
      The printer not only needs to recommend the profile you should use - he should also print to the same standard. This will mean him printing to the correct densities (lab values really) and dot gain.

      If he doesnt then it is not a disaster -if he proofs to HIS standard that helps - if colour matters then unless you are sure -see whether he can put an image up with a job he is running - with CTP it is much easier to do these days.
      Peter

      Comment


      • #4
        Re: Request for specifications

        I do know that and I did ask them what profile they recommend. They acted like I was the first person to ask that question. The exact question I asked was "what profile do you recommend for converting to cmyk?" It does not get much more straightforward than that. After much explaining, confusion and hesitation he said to use US sheetfed coated v2, but I think he just opened photoshop and told me what was there. There are so many complaints I see on this board about customers who supply bad files and have a lack of understanding, but how about the frustration of a printer not even being able to answer a simple question like, "do you prefer that profiles be embedded or not?" Of course if they don't know what you are talking about or seem unsure, the answer is no, but it is still frustrating.

        That is a good idea to see if they can work in an image Pete. So do you think Paul, without really knowing, staying below 90% will be safe for shadows? I was thinking about 2% for essential highlights so thanks for the conformation. Thanks for the tips gentlemen.

        Comment


        • #5
          Re: Request for specifications

          I would think keeping below a 90 on the plate would ensure that any detail you would want to keep would remain in a reproduceable boundry. But that is from a printer point of view,

          good luck

          Paul

          Comment


          • #6
            Re: Request for specifications

            These days, Sheetfed Coated V2 is your best bet. However, this produces separations in line with the old film/MatchPrint standard. Not a terrible thing, but a slight bit heavier ink lay than what most offset printers are heading toward today -- GRACoL, more specifically, G7, the latest revision.

            The last 10 years of the litho industry has been some ride. An uproar since film was replaced by CTP and whether or not to start printing sharper than the competition (since CTP provided the capability), or curve data to make CTP print like film, and therefore match legacy data (and have reprints match old jobs).

            US Sheetfed Coated V2 is that curved up version to match legacy data. G7 is somewhat of a compromise. Straight linear CTP prints very sharp (that's great) but it also loses a lot of print contrast. For printers that took the sharper linear CTP route, many clients complained of flat imagery. Or they push ink high in the hope of overcoming it. Some even altered the input data, but later sharing of that data with others makes for upset (things no longer match).

            But to answer your question, what profile to use when converting to CMYK (I think that's your question). The best would be what the printer recommends. But it appears you're not getting a straight answer. That's a clue, maybe find another supplier. Your second choice is good, US Sheetfed profile. That will give you a "decent" separation.

            Now, on to your question of tonal value limits, 2-3% is fine at the low end, but I find it odd to speak of 90% unless you're referring to a grayscale (K only) image. When speaking CMYK we talk total ink coverage, the sum of all colors combined, and typical answers range from 280% (web, for example, what US SWOP will produce, lacking punch) up to 340% (what we use). This is not a equal amount of each color, that's the art of separation, undercolor removal and gray component replacement, and is beyond description within a single posting.

            This total ink value also does not automatically determine shadow detail, much of that is dependent on the content. But the higher number will give darker (richer) solids. And muddy up lousy content. There is no magic button that makes it all work. A good scan, separated by an experienced color professional, set to an effective total ink coverage and produced on a good press by a competent operator... you see, there are many factors, and explains why every magazine doesn't look like National Geographic.

            Not having control, personally, over all these factors, you have to compromise, and choose something that will get you close enough. US Sheetfed works well for that, but it's dated. You could Google for GRACoL and download the free 2006 profile, that's pretty good. Or ask me and I'll e-mail you my G7 profile set to 340% TIC.

            Next, the subject of "embed profile or not embed profile." A sticky subject. Here's one answer: if every user understood what a profile was and its effect and knew what profile they were selecting..." I'd say yes, embed profiles. The problem is embedded profiles are like a loaded gun in the hands of a five-year-old. The Photoshop default is US SWOP. Color-wise it's close to sheetfed, but with lower total ink. So the result is flatter than it could be (made for web, no surprise). When we get these files with embedded profiles, we have to ask ourselves, "Did the user mean for this to be embedded? Or did it just happen by default?" We lean toward the accidental and strip out all profiles, unless the source specifically tells us, "Yes, I embedded, and please use my profile." Photographers are typical of this response, the only users so far that seem keen to profiles. They have to, in order for good color from their digital cameras.

            But there is another problem with profiles -- within most workflows, any profile triggers re-separation. Which sounds fine, even CMYK can have differing color spaces and need color management to convert from one flavor of CMYK to another (G7 to Fogra27 for example, when a book printed in the US is reprinted in Hong Kong). The problem is that workflows don't realize when the incoming and target profiles match, in which case color management isn't needed (no need to re-separate data that exists in the proper color space to begin with). So here exists another reason to strip profiles -- to prevent unwanted re-separation, the worst result of which is that K only objects come out the other end a build of CMY. Not to mention a finely tuned CMYK separation can turn to garbage.

            So the real answer is, you need to talk with your prepress department. If they haven't got a clue, that's your clue. Or use a trade prepress that does know (what we do, we're not printers), and have files prepped and proofed by craftsman, and printed wherever you please (we determine how they print). Communication is the key, and many printers/prep departments WILL communicate with you, even though at first it may seem they don't understand you, or you don't understand them. Keep trying, and be pleasent, avoid any urge to show off how much you think you know, and ignore if they try the same. It's normal human behavior when confronted by strangers. Get past all that and listen to how they do things. It may be different. The defintion of "right" is that it _works_. If their way of doing things gets the job done, listen and work with them. However, if what they do doesn't work, yes, move along.

            What's important is the proof, as it's always been in the litho industry. A good printer can make a proof and match that proof. Once you're confident of that, get the proof, adjust if you don't like it (NOT at the press!) and re-proof until you're satisfied. Then print to match that proof. That's how the process is supposed to work.

            Comment


            • #7
              Re: Request for specifications

              Hi again,

              +Now, on to your question of tonal value limits, 2-3% is fine at the low end, but I find it odd to speak of 90% unless you're referring to a grayscale (K only) image+


              I believe the question is "at what point does a tint become solid after we take into account of TVI on the press". my educated guess is about 90% maby a tad more but too dependent on ink weights, blankets and pressure to state 90-95% as a standard achievable figure. I see your point about TIC but from a designers point of view this is irrelevant (only my opinion and as im a printer not a designer so i could be wrong). Its as simple as if i have detail in a 95% tint will i see it on the sheet.

              Your point about achieving a satisfactory proof before it get to press is an great point to make, i have spent hours matching proofs with unreal densities as the customer has wanted to adjust color without the extra cost of a proof only to find when the job were to come in again there is another image on the sheet which was printed at standard densities.
              At my company the onus is on the press operator to pull the rabbit out of the hat and in an effort to please people we make poor long term decisions buy dropping densities out of standard tolerance. if i were to lift the job and ask for artwork ammends to match color i would be seen to be obstructive.

              Paul

              Comment


              • #8
                Re: Request for specifications

                William does reduction in dot gain caused by moving from neg to CtP make any difference to the tac in the printed image
                (I assume that the profile you have suggested is based on Neg printing contitions)

                Peter
                This is for my interest as I havent considered this before

                Comment


                • #9
                  Re: Request for specifications

                  If they are printing to GRACoL2006_Coated1v2, use that or the default U.S. Web Coated (SWOP) v2. U.S. Sheetfed Coated v2 is an old profile that is not in line with today's printing, and when printed it will look lighter than intended (lighter than what one would see on a calibrated and profiled monitor when doing soft-proofing). To see what would happen if the printer is printing to GRACoL2006_Coated1v2, soft-proof your U.S. Sheetfed Coated v2 separations with the GRACoL2006_Coated1v2 profile in Photoshop (checking Keep Numbers, Simulate Paper and Simulate Ink) (assuming a calibrated and profiled monitor).

                  Don

                  Comment


                  • #10
                    Re: Request for specifications

                    I will disagree (at my peril) with William.

                    1. Do not use the US Sheetfed profile. It's built from Matchprint. I would recommend using US SWOP Coated over the US Sheetfed. Not that I particularly like that profile, but odds are good that since that is default CMYK space for Adobe apps in the US, your print provider has been unknowingly working toward that print condition.
                    2. CTP displays *greater* print contrast. Dot gain goes down, we crank up the ink and the solids/shadows get darker. So, we have increased print contrast.

                    I will agree with William that the G7 profiles are "better". I prefer them, and use several variations/mutations. I would also ask, as William did, why you're using this print provider. Please, don't answer that. It's likely to throw me into a seizure.

                    bluskool, you haven't given enough information to make an educated guess about what conditions to separate to. What kind of paper are you printing on? I assume this is 4 color. Why do you need to know the "maximum shadow density"? Are asking about TAC? You can look up the black points of various print conditions via profiles (or data) from those conditions.

                    Minimum highlight dot is another matter, but completely depends on the paper/ink/screening to be used. In a sheetfed environment, using 21.2 micron stochastic we could routinely display a 1% (and smaller). So, what screening parameters are you looking at for your job?

                    > {quote:title=PeterA wrote:}{quote}
                    > William does reduction in dot gain caused by moving from neg to CtP make any difference to the tac in the printed image
                    > (I assume that the profile you have suggested is based on Neg printing contitions)
                    >
                    > Peter
                    > This is for my interest as I havent considered this before

                    Peter, a reduction in dot gain won't necessarily change the TAC, as that is really a function of the physical properties of the paper/ink/blanket/fountain solution combination. But, given lower dot gain you may find that you can push the ink harder without muddying up the image. Shadows should stay open longer, mid-tones won't appear so heavy.

                    rich

                    Comment


                    • #11
                      Re: Request for specifications

                      > {quote:title=PeterA wrote:}{quote}
                      > William does reduction in dot gain caused by moving from neg to CtP make any difference to the tac in the printed image
                      >
                      By itself the move from neg to ctp does not have any effect on what percentage each color is to the rest, but it could if an operator chooses to re-separate and change the total ink coverage (I prefer the term TIC, *ink* rather than area). Perhaps you mean, "Are higher TIC values possible with CTP?" Indeed they are. And going back to the original topic of this thread, one thing to realize is that in the past (days of film), one of the reasons 90% was difficult to hold on press was due to what was lost in the frame while plating. That is one of the fabulous benefits of CTP, that the higher shadow values maintain far more detail than was possible with film/analog plates exposed in a vacuum frame.

                      Comment


                      • #12
                        Re: Request for specifications

                        > {quote:title=rich apollo wrote:}{quote}
                        > I will disagree (at my peril) with William.

                        No peril here, Rich. <grin>

                        > 1. Do not use the US Sheetfed profile. It's built from Matchprint. I would recommend using US SWOP Coated over the US Sheetfed.
                        >
                        I only suggest the Sheetfed profile because many printers still print to that standard. More than you might imagine. Before this month when we switched to G7, the standard we had been using to supply plates to a great many printers was also based on film/Matchprint (in the interest of legacy data). Similar to US Sheetfed, only our own recipe, somewhat different undercolor and total ink coverage. We decided enough time had passed and it was time for us to use up-to-date standards, so now we provide proofing and plates to the G7 standard (as well, the time had to pass for a decent standard to develop, now it has).

                        And really, the standard we'd been using was not all that far from G7. Just a bit heavier, slight, as is to be expected between a film and CTP standard. And when clients use US Sheetfed Coated to separate, the results were acceptable. It wouldn't even be that bad to use the profile under the G7 standard. The images will simply end up a bit cleaner, brighter, and in the end, most clients are pleased. It's not like the difference between the profiles/standards we're talking about turn skins tones purple.

                        I do agree with the logic that many printers will go with defaults, making the US SWOP a better choice. But I will say, in my examination of US sheetfed versus the SWOP profile, the "general" results are quite similar, meaning the overall look of images is similar, but upon closer inspection it is clear the SWOP profile is geared toward much lower total ink (around 280, icky, with giant flat areas in C and M where shadows go). To be expected for a typical web press. That is the only reason I would not recommend the profile. It will not give the best looking separation.

                        > 2. CTP displays *greater* print contrast. Dot gain goes down, we crank up the ink and the solids/shadows get darker. So, we have increased print contrast.
                        >

                        Ah, but not at proper ink film thicknesses. Sure, even with film we could "crank up" the ink and increase print contrast. CTP lets us get away with it from the standpoint of dot gain, but even CTP will not keep heavy ink films from causing unwieldy ink-water balance, picking, piling, emulsification and sheet set-off, not to mention the dollars down the drain in the cost of laying down excess ink.

                        A better approach is to develop an effective proof, and develop effective curves for the plate so the press can get similiar print contrast while matching that proof without having to crank up the ink. Save the money, ink is expensive.

                        > I would also ask, as William did, why you're using this print provider. Please, don't answer that. It's likely to throw me into a seizure.
                        >

                        Let me guess -- the estimate was 30 bucks less than the other guy. Oops. Sorry about that seizure... <grin>

                        Comment


                        • #13
                          Re: Request for specifications

                          you can adopt the new isocoated_V2 profile, set the ink limits to 300 and your sheetfed will be able to print with good result...

                          Comment


                          • #14
                            Re: Request for specifications

                            I think ISOCoated V2 300 is the one you are talkiing about - it has been designed for web printers who wanted higher tac for covers - I think ISOCoatedV2 has a tac of 330.- which is for the commercial market

                            Peter

                            Comment


                            • #15
                              Re: Request for specifications

                              > {quote:title=William Campbell wrote:}{quote}

                              >

                              > Now, on to your question of tonal value limits, 2-3% is fine at the low end, but I find it odd to speak of 90% unless you're referring to a grayscale (K only) image. When speaking CMYK we talk total ink coverage, the sum of all colors combined, and typical answers range from 280%

                              I asked for a maximum shadow density estimation. It doesn't matter whether you want to answer that in terms of TAC or K. In practice, I could really use either in Photoshop to get an idea of when the shadows will fill in.


                              > ...you see, there are many factors, and explains why every magazine doesn't look like National Geographic.

                              Not to mention every magazine doesn't have the best photographers in the world.


                              > But there is another problem with profiles -- within most workflows, any profile triggers re-separation. Which sounds fine, even CMYK can have differing color spaces and need color management to convert from one flavor of CMYK to another (G7 to Fogra27 for example, when a book printed in the US is reprinted in Hong Kong). The problem is that workflows don't realize when the incoming and target profiles match, in which case color management isn't needed (no need to re-separate data that exists in the proper color space to begin with). So here exists another reason to strip profiles -- to prevent unwanted re-separation, the worst result of which is that K only objects come out the other end a build of CMY. Not to mention a finely tuned CMYK separation can turn to garbage.

                              I never had any doubts. I don't embed cmyk and a situation where it would make sense to has not come up yet for me (although I know there are controlled environments where this works.)

                              > So the real answer is, you need to talk with your prepress department. If they haven't got a clue, that's your clue. Or use a trade prepress that does know (what we do, we're not printers), and have files prepped and proofed by craftsman, and printed wherever you please (we determine how they print). Communication is the key, and many printers/prep departments WILL communicate with you, even though at first it may seem they don't understand you, or you don't understand them. Keep trying, and be pleasent, avoid any urge to show off how much you think you know, and ignore if they try the same. It's normal human behavior when confronted by strangers. Get past all that and listen to how they do things. It may be different. The defintion of "right" is that it _works_. If their way of doing things gets the job done, listen and work with them. However, if what they do doesn't work, yes, move along.
                              >

                              Our prepress is quite competent and we supply great, RIP-ready files to the printers we use. But alas (sigh), I don't pick who we work with. I just deal with it. Which is why I am thankful that this board exists.

                              Rich,
                              Next time, I will find out the paper type (too late for this job.) That would definitely help the guessing. As far as why I would want to know maximum shadow density...so I know when detail becomes visible in shadows. Am I the only person that asks this question in this way?

                              Dan R.

                              Comment

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