Exposure time for Murakami SP-Pro with M&R Starlight UV LED Screen

[Rubysky]

Glad to see much response Murakami Japan gave me that 60 sec mark as starting point. They do not have M&R starlight so they throw that 60 sec number base on the exposure unit they have in their office.

I notice a lot people in this forum do 1;2 or 2;2 coating on the screen. Murakami rep told me to do 2;2 let it dry and do 1;1 again. No, degrease.... Just use sticky roller tape to pick up dirt from the screen. They don't even sell degreaser here... I tried to purchase from the US but the liquid chemical is really hard to pass custom these days. Dish washing soap is bad so is there any other alternative? Or any shop out there that willing to ship chemical to Japan?

Thank you so much, guys.

[TCT]

2/2 and THEN 1/1 - sounds like someone is trying to make more sales... We have been doing 1/1 for over a year now probably. We are pretty much a DC/WB shop though. When we did plastisol we would coat 2/2. That was Murakami HVP.

2/2 then 1/1 is just a waste.

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[Dottonedan]

No, it does not depend on "my shop".  M&R, professionals they are, confirmed the times using same mesh/emulsion/coating to make sure there wasn't something off with the unit or with our process. 

And yes, if you are using diazo added emulsions, the claim that LED is faster and cooler is absolutely bunk.  Apparently nobody tested that prior to selling the units and they weren't aware that certain diazos would have such long exposure times.  The units overheat at the times needed to shoot diazos- our entire array needed replaced due to a heat warped board. 

I'm hesitant to address your comment about an i image working faster than a 5k MH shooting multi up....I'll say that I love the concept of "insert screen, image, expose, resolve".  I think that's great and a very natural workflow.  But it is not faster than standalone imaging and MH shooting multi up. 

Again, we use LED so it's not that I'm against it.  Just putting down some facts.

Yes it does.


I don't know much about "cooler".  I have not been involved in, nor heard marketing it to be "cooler" than this or that.  I've only heard them to say that it doesn't put off a lot of heat (if much at all)..and that has been my experience... and uses less energy. So I'm positive that what you say,  is totally true and coming from you, I'd expect it to be so. But, having said that, I know (first hand) it's not "typical" in any of my situations to be very hot or hot enough, to cause a problem for all people. Again, my point that you and your shop have to be somewhat different than the average beast.


I say that from putting in and working on machines at over 160 different shops in me little time I was there with at least 15% of them being waterbase discharge printers.
Now, the LED exp have not been out for 10 years so we don't have a ton of people chiming in to provide that kind of feedback. I'll be the first to say, I'm no expert on the temp thing. You have experienced something with that. So you have every right to say your experiences. I didn't have that experience. I will say tho, I've not heard (one) person in the field say, Damn man, these things get hot! It melted this or that on it or I had to buy a new X thingy cuz it melted inside. Notta one, but that doesn't mean it does't happen. I might have jsut not heard about it while there.  I musta went 2 years before ever having to replace a print head in one of the older machines and after I did, it continued to be a rarity. During my first year or so, I started to think that they just never went bad till that one day when I finally did replace one.


I don't claim to dispel your facts. They are facts indeed (for you) and that is my only point. What I'm saying is, I guess I take issue with the "blanket statements" as if it's done and done man, no if's but's or why's. It's THIS way and nothing else. I don't agree with that.


I just want to make note, that the experiences at one shop (given that you are a seasoned and more so a top level waterbase and discharge printer, ) the experiences at your shop may not apply (to all) Diazo users in this industry but could very well, apply to many or most waterbase printers. For example, you have previously and in this instance, said
A, a 5kMH is far superior in every way).
That's false.  It's false simply because you, do not run every 5KMH in the industry under every scenario. Trust me, there are many extreme differences in shop to shop and their particular needs. That's obvious, because there are shops out there that do print waterbase day in and day out, doing high end sim process...and have ditched their MH. Whatever it had been, 1, 3 5 I don't know.  And you use for knowing that it's not (as good) as your 5kmh.  No issues.  So I'm say'n, (it does work for PP and it does work (for waterbase printers). Your whole statement about the 5kmh being FAR superior, seems null and void.


And I'll wager or rather or come right out and say, You probably know twice what I do about exposing screens, cuz you live it and especially (in your shop).  Me, I was just there at various shops long enough to do it for 1-2 days per week. So don't get me wrong. I'm not pushing M&R and I'm not saying "I know more than you"...but I know what is being done and had been done on these machines with all different emulsions...despite what you experienced in your shop.  An I'll say this.  To give a blanket statement as if it's fact that it pertains to ALL shops who use any Diazo, is not a good or accurate statement.


I'll also say, that I'd rather have a 5K MH (for me...and for what I would want to do) if I had my own shop and the $ to buy either, but then again, I'd also prefer to be a millionaire or at least own my own shop.


My comment about the I-Image working next to a 5k MH doing 4 up, (did not) and does not say that it was faster than. That wasn't the point of mentioning the 5k.
I said "that 5k MH was doing 4 screens at a time that exposed at 8 min on 110 mesh's whilst thy were clicking away on the I-Image". Actually, it was longer than just 8, but I rounded. I've seen that happen twice. Two different shops. The one shop did 8 screens at a time. A whole wall, but it was for a longer exposure time. That shop had already had three different brands of DTS machines sitting right there (partially in use) whilst I installed an STEII.  They were a big and busy shop. Now, I get that. I get why to use a 5k and expose 4 or 8 screens up at a time. I don't have anything against an 8 min exposure time (for 4 screens). That's good stuff.


One more thing. I did't quite understand the one point you made about there professionals.

M&R, professionals they are, confirmed the times using same mesh/emulsion/coating to make sure there wasn't something off with the unit or with our process. 

.  If you are saying that M&R sent in some people to see what the dillio was, (running exp test, coating etc), than I am still not convinced.

[TCT]

My comment about the I-Image working next to a 5k MH doing 4 up, (did not) and does not say that it was faster than. That wasn't the point of mentioning the 5k.
I said "that 5k MH was doing 4 screens at a time that exposed at 8 min on 110 mesh's whilst thy were clicking away on the I-Image". Actually, it was longer than just 8, but I rounded. I've seen that happen twice. Two different shops. The one shop did 8 screens at a time. A whole wall, but it was for a longer exposure time. That shop had already had three different brands of DTS machines sitting right there (partially in use) whilst I installed an STEII.  They were a big and busy shop. Now, I get that. I get why to use a 5k and expose 4 or 8 screens up at a time. I don't have anything against an 8 min exposure time (for 4 screens). That's good stuff.

I would be PISSED if it took 8 min to expose screens!!!

We actually did 4 up on the wall with the 5k unit. It is still semi set up for our all over screens. It has been a while and I'm not at work so I don't have the light units we have recorded. I want to say for us it was around 50-85 light units(roughly 4 min) to expose a set of screens. The high end was a 135S mesh coated 2/1, low end was the 380 coated 1/1.

[Dottonedan]

My comment about the I-Image working next to a 5k MH doing 4 up, (did not) and does not say that it was faster than. That wasn't the point of mentioning the 5k.
I said "that 5k MH was doing 4 screens at a time that exposed at 8 min on 110 mesh's whilst thy were clicking away on the I-Image". Actually, it was longer than just 8, but I rounded. I've seen that happen twice. Two different shops. The one shop did 8 screens at a time. A whole wall, but it was for a longer exposure time. That shop had already had three different brands of DTS machines sitting right there (partially in use) whilst I installed an STEII.  They were a big and busy shop. Now, I get that. I get why to use a 5k and expose 4 or 8 screens up at a time. I don't have anything against an 8 min exposure time (for 4 screens). That's good stuff.

I would be PISSED if it took 8 min to expose screens!!!

We actually did 4 up on the wall with the 5k unit. It is still semi set up for our all over screens. It has been a while and I'm not at work so I don't have the light units we have recorded. I want to say for us it was around 50-85 light units(roughly 4 min) to expose a set of screens. The high end was a 135S mesh coated 2/1, low end was the 380 coated 1/1.

Well, as you know, yes, that's one exposure for 8 min, but that's like 4 screens at 2 min each. So not "that horrible" I guess it decreases as you pull back further to encompass all screens for a good exposure all over each screen. I'm sure their bulb just needed replaced.

[Evo]

We are still dialing in our new Starlight but with diazo emulsion we are more in the 15 to 20 second range. More than that we are seriously pinching detail but we're still in the test phases seeing if we get breakdown on press.

BTW - Chromaline CP Tex, using CTS rails, no glass.

[Admiral]

This may help since it's Murakami but for SP-1400 with no glass we do:
28 sec for 225S mesh
40 sec for 150S mesh

Coated 1/1 sharp edge.

[ZooCity]

Haha, ok Dan aside from power consumption and bulb life, tell me in what way LED exposure is superior to MH, for any shop. 

To clarify, my comment about M&R being pros was to be taken literally.  We have longer times than they say you should have for the unit and they took the time to test and confirm that.  If you use our emulsions and fully expose your screens the results should be about the same on any starlight unit.  That is not a shop to shop thing, and that's according to them, not me. 

I'm ok with it all but I miss the MH is all I'm saying.  Someday the LED units will get there I'm sure. 

[Frog]

Haha, ok Dan aside from power consumption and bulb life, tell me in what way LED exposure is superior to MH, for any shop. 

To clarify, my comment about M&R being pros was to be taken literally.  We have longer times than they say you should have for the unit and they took the time to test and confirm that. If you use our emulsions and fully expose your screens the results should be about the same on any starlight unit.  That is not a shop to shop thing, and that's according to them, not me. 

I'm ok with it all but I miss the MH is all I'm saying.  Someday the LED units will get there I'm sure.

The first obvious variable that comes to my mind on this statement is that some shops may use the same emulsions, but either not the same mesh counts, or coat to the same EOM. I see more than one post in which someone coats the same mesh thinner (with an insufficient EOM) for detailed work, something that could bite them as it also introduces the "jaggies" from the mesh pattern

[ZooCity]

Totally Frog.  It does make it hard to swap notes for sure.

What M&R did was go to the trouble to use our same mesh, emulsion, coating (even down to the coater I believe).  That was what I wanted to clarify since Dan asked- they really dug into it and the times, within a little variance, are repeatable. 

[Rubysky]

Hi,
5 Sec Vacum and 60 Sec exposure for White Mesh 155, 2;2 Murakami SP emulsion. The emulsion comes right off when I spray with high power water pressure. I can actually pill the emulsion row by row with the water. Is this issue under expose? The graphic could wash out within few second. Then the graphic begin to wash out as well.

Thanks.

[Dottonedan]

Under.

[jvanick]

Hi,
5 Sec Vacum and 60 Sec exposure for White Mesh 155, 2;2 Murakami SP emulsion. The emulsion comes right off when I spray with high power water pressure. I can actually pill the emulsion row by row with the water. Is this issue under expose? The graphic could wash out within few second. Then the graphic begin to wash out as well.

Thanks.

get yourself an exposure calculator...

gut feeling is to double your exposure time and try again.

[Frog]

Glad to see much response Murakami Japan gave me that 60 sec mark as starting point. They do not have M&R starlight so they throw that 60 sec number base on the exposure unit they have in their office.

Ruby, this goes back to what Murakami told you. 60 seconds is your starting point for testing. In this context, trying a range of half of that to twice that. 30 sec - 120 sec.
If you don't have an exposure calculator, or if you want to see the results on the actual media you use for your "films", do a manual step-wedge test.
Murakami themselves give this same advice and offer these instructions on how to run a test.

[Rubysky]

Thanks for the reply I'll coat several screen today and try again. I do have exposure calculator from Chromaline.