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Splotchy Blacks -- Any Ideas?

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  • Splotchy Blacks -- Any Ideas?

    We often have issues with getting nice solid blacks off of our Itek 975pfa. We use a DPM 2340 platemaker and paper Megaplates with a linescreen of 133 (or close to -- can't remember). Our pressman is very lazy so I often sense that I'm getting BS'd by him. He says our "press isn't made for that". He says the same about halftones. He argues that it was originally just designed for speed and not quality.

    Here's what I know: 1) It appeared he didn't have his ink up enough on this but I don't think that is the entire issue -- he acknowledged that, 2) the blankets were changed quite recently. I have no reason to suspect that pressures are off, 3) we ended up changing the chemicals in the platemaker within a couple days after printing this because we were having halftone quality issues. Changing the chemicals fixed the halftones but the pressman is saying that old chemicals would not affect the quality of solid blacks.

    Any ideas on what might be the cause here? Am I getting BS'd by our pressman? He says he has "been having trouble with solids lately". Would old chemicals in the platemaker cause poor quality in blacks? Could cheap paper be part of the problem? I would pay to get this fixed if it is indeed a press issue.


    splotchy.JPG
    Last edited by jpfulton248; 01-03-2017, 02:03 PM.

  • #2
    First off, your press operator is correct. It's not a machine one expects top quality from. Also, the machine is old.
    That said, and based on your photo, the first thing that comes to my mind is the paper. It looks like you're using a paper that's quite porous. I can't recall whether that press has 2 ink forms or 3. I suspect 2. It would be a bit of a job to run a nice solid on the reverse type area while keeping the halftone open. Although I can see where a little more ink is called for. The consistency of the ink could also be an issue.
    I'd suggest putting several sheets of a smoother stock about 10 sheets from the top of the feeder and when you hit those sheets have a look at the difference in quality. That might give you your answer.
    There's a long history of trying to make small offset machines like AB Dicks etc. perform beyond their capabilities. The old saying is, if you can run an AB Dick you can run anything. Itek, Ryobi, Hamada was an improvement in that size of equipment, but still . . .

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    • #3
      Pull some dry solid prints. Blank plate no dampening and see how the black prints. This might give you an indication if your pressures are not right. Does your pressman check his press every so often, roller pressures, settings etc. How about the dampening system on the press is it well maintained and is the fountain solution being dosed correctly.
      Cheap porous stock will certainly give you bad solid prints.
      You need to contact the press manufacture and tell them your pressman says their presses are just built to produce low quality fast. What a load of BS.

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      • #4
        Regarding pressures... I don't believe he ever checks them really. Over the years I've bitched about things and have gotten him to check them and they haven't ever been off which is why I said I don't think the pressure is the issue. Paper seems likely as we are running the cheap 20lb uncoated. Interesting that the two first comments conflict regarding the press and expectations of quality. Any chance old plate maker chemicals would affect the quality of solids?

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        • #5
          20lb bond isn't a good choice. Use a smooth offset or laser stock (something less porous) and you'll see improvement. Coated text would be ideal, but sometimes can create it's own set of problems on a small press. Old chemistry doesn't help.
          Re press and quality: These presses — often referred to as duplicators — were essentially replaced with photocopiers and are all no longer in production. I think that says it all. It's like comparing a Volkswagen Bug to a Jaguar in the world of offset printing. They made tons of money for business owners during the 'instant printing' heyday of the 60's, 70's and into the 80's. Then their popularity started to decline as copier technology increased. Sure you could get some decent work off them, but it could be a chore and dependent of the background & skill level of the operator. A lot of shops keep such a machine around to run the occasional oddball job. Small size, NCR, small PMS colour jobs, stuff that won't go through a copier. etc.

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          • #6
            I agree with Keith. I have two presses that I run, a ryobi 2800 which is one of the duplicators he's talking about, and a heidelberg kord. If I ran that job on the ryobi, I would have a pretty tough time and would expect the quality to turn out like it did in your picture. On the kord, the solids and halftones would be near perfect without much hassle.

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            • #7
              Well, I'm looking into trying a smooth 50# text instead of the 20# bond we run. I was just quoted $23.06 per thousand for 50# Accent Opaque vs the $15.84/m or something we are paying for 20lb.

              99% of the jobs we run are identical. Booklets -- all black over black, 20# bond, mostly text, some halftones and some reverses. We run most of our covers digital. This business has been in place since the early 90s. As time has progressed more and more people are sending "camera ready" artwork for advertisements that we place in our publications and as such we end up trying to print art that has been designed well, but not designed for 1/1 on a duplicator at 133lpi.

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              • #8
                Hello "jpf"

                Questions - 1) Does the solid image area look "OK" onthe plate ??

                2) USE Metal Plates !

                3) Follow "Cornish's " advice

                4) And this is important..... Hold a blank sheet of the paper up to

                the light - it should look Uniform Translucent ???

                Regards, Alois

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                • #9
                  1) Yes
                  2) My press operator won't give up his plate inserter which we have only been able to work with paper plates also I think they only upgrade we would be able to make would be to poly plates. I don't believe the DPM 2340 can do metal plates.
                  3) Ok
                  4) I'll check this

                  Thanks!

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                  • #10
                    Hello "jpf"

                    You are correct DPM Platemaker only process "Cheap and nasty Paper/Polyester Plates"

                    think of "Planet Earth" using Metal Litho plate which are "Recyclable" !!!!!

                    Using paper/polyester plate - equal poor ON Press performance

                    Regards, Alois

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                    • #11
                      Originally posted by jpfulton248 View Post
                      1) Yes
                      2) My press operator won't give up his plate inserter which we have only been able to work with paper plates also I think they only upgrade we would be able to make would be to poly plates. I don't believe the DPM 2340 can do metal plates.
                      3) Ok
                      4) I'll check this

                      Thanks!
                      Your answer #2 is the one that bothers me the most . . . who is the boss here . . . IMHO I would be looking for a new pressman with a "can do - no problem boss" attitude.

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                      • #12
                        All pretty much seem to be great suggestions to help provide some remedial relief.

                        However, just curious; what black ink do you use? Please be specific as possible. Brand, nomenclature, product number and container type to be specific. You never know.

                        D

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                        • #13
                          I agree with the suggestion that your expecting too much from your duplicator. Your pressmans reluctance to follow your suggestions to give up on his plate inserter, may just come from the fact that he already knows, as many of us here do that your trying to make a silk purse from a sows ear. Sometimes people need to be told what they just don't want to hear. My guess is that he has just grown weary of your unreasonable expectations. There is a reason why people purchase real presses as opposed to duplicators. There are also reasons that people pay the premium price that you seem to balking about for a quality sheet of paper thats manufactured for the purposes that you describe. Shit in equals shit out!!!

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