# film positive vs. vellum



## lousentdreem (Sep 3, 2006)

the printshop that used create my film positives for me went out of business.
my screen printer says over the phone that they are using vellum now.
who knows what the differences are? what else is available? how is a transparency different from a film positive?


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## Squirts (Feb 17, 2006)

lousentdreem said:


> the printshop that used create my film positives for me went out of business.
> my screen printer says over the phone that they are using vellum now.
> who knows what the differences are? what else is available? how is a transparency different from a film positive?


 From the printers end a transperancy will have a slightly different exposure time then vellium and or polyester paper which looks alot like vellium.... Vellium and polyester look opaque untill held close against something then you can see thru it.... If you held either up in front of you you cant see thru it...but if you lay it on ....lets say a magazine... you can see the magazine clearly thru it as if it was tranparent.... lift it off the surface and it looks opaque again.... if they use an inkjet printer they will probably use vellium if they are using a Laser they will probably use the polyester.. if this is the type of film positive they want to work with instead of the clear transparent type... I, Myself, use the Polyester with a Laser Printer......
With all this said, i dont see why your printer cant use whatever you provide, Clear Transperant, Vellium or Polyester... Its not something that has to be setup for just one an not the others, its just a matter of adjusting exposure times... which if they have been in business more then a day they should have no problem with.. Good Luck Chuck


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## Fluid (Jun 20, 2005)

> i dont see why your printer cant use whatever you provide, Clear Transperant, Vellium or Polyester... Its not something that has to be setup for just one an not the others, its just a matter of adjusting exposure times... which if they have been in business more then a day they should have no problem with


As a contract printer I can say this is partly true but not totally correct. Depending ont he light source the supplied material for burning screens can cause major problems - Not just adjusting exposure times. With the many wide variety of materials used exposure times could be drastically changed for the material. Depending on what is being burned (art wise) can alos come into play big time. Shrinkage plays a major part in the type of films used as well.

If you are going to use anything other than a high quality film I would send a sample to your printer for them to test and be prepared to be billed. I will not accept anything but high quality film and I do not gurantee the prints from customer supplied films due to the many issues that may arise from bad art to having to burn the film a ton of times trying to get a proper burn.

www.oyo.com has a fim output service and the cost is minimal for quality thermal imagesetter output and film. I have been using their machines and film for years and other than a true imagesetter this is the best. 
The next best is film used with epsons modified to print films.
www.usscreen.com sells a good package. I have the 1800 as a back up for my back up, just in case.


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## Squirts (Feb 17, 2006)

Fluid said:


> I will not accept anything but high quality film and I do not gurantee the prints from customer supplied films due to the many issues that may arise from bad art to having to burn the film a ton of times trying to get a proper burn.http://www.


 You bring up the most important issue... Quality... No matter what the film material used.. For simple Prints theres less chance of a problem however for complex prints I feel that, a person really should be experienced in the whole process and not just a part of it... Because , as you have mentioned, theres just too many varibles...


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## lousentdreem (Sep 3, 2006)

So I take that to mean it's a quality issue. Actually I prefer using printshops 
for the films because they tend to catch my mistakes prior to printing.


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## lousentdreem (Sep 3, 2006)

well at least I know how to spell it now>thanks.


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## thebrain1 (Mar 12, 2007)

The difference is the vellum is an opauqe paper and takes more expousre time.


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## RichardGreaves (Nov 7, 2006)

lousentdreem said:


> the printshop that used create my film positives for me went out of business.
> my screen printer says over the phone that they are using vellum now.
> who knows what the differences are? what else is available? how is a transparency different from a film positive?


Who is making the art? You can provide your screen printer with the digital file and they will output it with their laser printer on 'vellum' textured transparent paper or textured polyester.

Laser output needs a textured surface to hold the extra toner needed to stop Ultra-Violet light when the screen is exposed.

EPSON printers with piezo heads are the only reliable inkjet printers that can be customzed with software printer drivers to shape halftone dots and increase the ink deposit to stop UV light.

Film (no paper) must have an absorbent coating to hold the ink. Dye inks can be used with a swellable coating or nano porous coating designed for pigment inks. EPSON stopped making dye inkjet printers in 2003.


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## prepress manager (Dec 1, 2007)

*Re: film positive vs. vellum - hp vs. Epson - HELP*

Hello,

Very interesting post and I learned allot. Since I am a litho prepress guy this is all pretty new to me. We have a really big commercial printing business. Now my company got into screen printing and I need to create film positives for production. We have been trying on some clear material off our HP z6100 and have some promising tests so far.

The HP cannot recognize the material, has sensors, so the only one that works is one with white strip all along the sides to help the HP manage the end detection of the material. I see so many references to using Epson for this process. I have the go ahead to get any printer and material that I want to do this task. But I need to do it right away.

You guys seem to have a good grasp of this subject. My question/situation is this. Boss says you have to be making good quality positives by Friday afternoon that are 60" wide. The production is used to having a luscher jetscreen but it is going out of service. The jobs are high quality POP signage are screen printed on big 5 color UV lines. Need from 30 to 70 positives a day. Expense is not as inportant as doing it right and nailing it.

What device and substrate would you get to do this job. Thanks in advance for your input because I really need help quickly and am out of my element with this screen printing stuff.


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## RichardGreaves (Nov 7, 2006)

*HP vs. Epson vs. Lüscher Jetscreen*

435 minutes per shift divided by 70 positives is about 6 minutes per positive. That throughput will take 2 shifts. RIP software always makes the output slower, and increasing ink density to stop UV light slows output.

As you are a litho guy, I'm sure you have access to a transmission densitometer. I doubt it your Designjet Z6100 will achieve UV dMax greater than 1.9 without RIP and the only company that supports separation software for the Z6100 is Wasatch SoftRIP. You will also have some problem finding inkjet film with a white edge stripe to make the Designjet think it is printing on paper.

SoftRIP SP for Screen Printing
Call Wasatch and ask what UV dMax they can achieve. Ask them how they beat the paper sensor.

If not, it's off to the store to buy an Epson 11880 - US$15,000.

PowerRIP (Florida), SoftRIP (Utah), FastRIP (Phoenix) and AccuRIP (NY) all support the 11880.

Why is your company retiring their Lüscher Jetscreen and going back to positives?


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## prepress manager (Dec 1, 2007)

*Re: HP vs. Epson vs. Lüscher Jetscreen*



RichardGreaves said:


> Why is your company retiring their Lüscher Jetscreen and going back to positives?


Jetscreen has wax, wax to buy, wax to remove, large service contract, yada yada. Consensus is that the Gigasetter film was working better but cost more. If we can make cheaper positives by inkjet, should save money, also a jetscreen taking 20 minutes a pop is slower than inkjets.

Hello, thanks for the info. We have a material coming that has white strips and should work with HP. Our density is OK but needs more beef, so we are tweaking profiles from a stripped backlit profile and modifying it now. Today we were tricking the edges by putting white tape on it to get small test positives off.

RIP: We have an Esko-Graphics SCOPE that makes separations to screened 1 bit tiff. So, this we just need to pass on and image without screening it. We have Onyx RIP and seems like we are getting a halo or some spatter around the dots, not breaking clean, like bitmap should. Seems to do better with color mgmt. off for sure. We have a ps rip on the z6100 so we tried sending direct now, see how hard the edges are that way.

So, atleast I am down to the imaging only part, density, ink adherence and substrate.

It sounds like if my HP experiments are not working, I should go with Epson? That seems to be what I read that everyone is doing it on an Epson. How are these RIPs at taking an already screened 1 bit tiff and giving me a hard dot? That seems to be a problem right now. Looks like the RIP sees this 1 bit tiff and is not respecting that it is line art? Anyone know how to get that to go through an onyx?


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## prepress manager (Dec 1, 2007)

*Re: film positive vs. vellum - hp vs. Epson - HELP*



ImageIt said:


> Why don't you just get some white tape and add the mark the HP is looking for?
> 
> fred


The HP will error as soon as it runs out of white tape on BOTH sides. So, we used white tape to execute tests but since we need 3 to 5 rolls a day of output, that will not work as a long term. The HP uses that white to monitor not just detect edge, as soon as runs out, bam, error.

We have 2 different substrates coming tomorrow that are for the HP and have white edge both sides end to end. By taking a backlit profile and tweaking it, we got really solid density, one dripped ink off the pages.. We edited the profile till it dries OK but piles on a nice thick black.

A guy PM'd me fro screener's choice and he is testing a sample of our file to compare the epson w/his rip vs. the HP with the Onyx. Our next challenge seems to be getting a crisp edge on the dots without as much spray. Not sure but it looks like the Onyx is putting a little stochastic edge on dots. Since it's 1 bit tiff going in, we are trying to get as sharp as we can. Hopefully tomorrow I will be making positives 60" wide on the HP, or maybe I will order the 60" Epson. One guy on another forum saying the dot will be cleaner, sharper from Epson.


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## buzzbox (Oct 24, 2007)

I'm confused, you say high quality signage. I guess that's is a relative term but i only know of what i produce here in my shop. If you are usiing an inkjet to produce film positives there is no way you are anything close to high quality. We use an Imagesetter to produce film positives at 2400 dpi resolution. The edge definition on a high quality inkjet dot is barely sufficient or satisfactory to produce high end screen printing. You can get away with it on t-shirts tho.


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## buzzbox (Oct 24, 2007)

Speaking of RIP's i use adobe acrobat pro to rip my film. works to perfection for t-shirt's and pop displays.


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## suzzyq (Sep 25, 2008)

My question is for screen printing textile separations using a Laser printer vs Ink jet printer.....we use art laser vellum printing on a Xante printer and the production dept is still using "toner aid" to make it darker...we print out at 1200dpi (for more coverage) at 55lpi w/elliptical 
dots ....any suggetions to skip the toner aid ....i.e. burn time etc....or should we look into getting a ink jet printer or change to another type of vellum....thanks for all your help


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## idesigninohio (Dec 14, 2012)

"I, Myself, use the Polyester with a Laser Printer......" Hi. Are you using the laser printer and polyester for multi color jobs as well? 2-3? We are using kimodesk vellum off our laser and my printer won't accept multi color off laser. What brand of laser printer do you use?

Thanks!


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