Problems with print quality

[ahgrafx]

Hello everyone,
I am using a mutoh VJ-1624 and am somewhat new to using them. I'm using the same settings as the previous operator and am getting this kind of an anti aliasing problem with my print. It is started out as vector and im outputing as pdf from illustrator and then saving as a jpeg in photoshop at 100dpi. You can see the problem in the curves of the S. is it maybe the dither? for ripping i am using photoprint dx mutoh. many thanks for your help.

 

[J Hill Designs]

why are you rasterizing it?

 

[ahgrafx]

sorry for posting in the wrong area, im still new.
i am rasterizing because pdfs take forever to rip on the machine we have the rip software on. It is my understanding that the rip software is rasterizing before printing anyways right?

 

[ahgrafx]

in the digital file it isnt this jagged in those areas

 

[bob]

First, dither has nothing to do with it. Dither is the algorithm that reproduces a particular image pixel my integrating just the right combination of CMYK printer dots.

If the original is in vector form why would you want to rasterize it? Other than, as you previously noted, to make it RIP faster, which I have a hard time understanding. Bitmaps generally take much longer to rip than vector objects. So just what is in this .pdf file? A .pdf is just a collection of objects, you might want to review just what settings you're using to create it. Nonetheless, I print bitmaps all the time, generally at 150ppi, and never have visible anti-aliasing.

Perhaps you might also review just how you're creating this bitmap. If you open the file you're about to print using whatever software you're using does it exhibit the same anti-aliasing?

 

[Supergirl]

I actually print on my mutoh, using the same rip, .ai files directly.

If i need to flatten it in photoshop, i do it at 300 dpi and save as .tiff

never had visible anti-aliasing.

 

[Biker Scout]

Always print in this order: .eps, .ai (if RIP accepts it) .pdf, .tif, .png, .jpg, .bmp

If you start with vector files, try to print them as vector files. They actually only contain mathematical points, rather than pixels. Which is why you can scale vectors up and down without getting all jaggedy.

Never print less than 150dpi for anything that's going to be seen from more than 6 ft away. Posters, and decals stuff like that you can print at 300dpi, but I've learned a trick that helps RIP faster and keeps file size down. The human eye can't tell the difference between 300dpi and 200dpi. So that's what I use most of the time. (Now the 150dpi thing doesn't count if you guys are printing actual billboard sized prints, but somehow I doubt that. So we can cover that on a different post)

If you are having specific print issues with .pdf or .eps files, whether it's unexpected color shifting, font issues, shadows, knockouts and transparencies etc... that's when you open the file in PhotoShop, rasterize at 150dpi, 200dpi or if you really think you need it 300dpi. Then flatten the file and save as a .tif and re-print. Sometimes experiment with saving the file in RGB color space and see what kind of results you get versus CMYK color space. You'll sometimes be pleasantly surprised by the results, and may adjust your workflow accordingly.

Good Luck!

 

[bob]

Not quite. most non-mutant people find it difficult if not impossible to visually discern 1 part in 100. That's why halftones were traditionally made with a 130 line [dpi] screen. At 130 lines the screen becomes more or less invisible to the naked eye.

As far as printing various resolutions keep in mind that ratio of the printer resolution to the input image resolution should be 4:1 plus or minus. Thus if printing at 720dpi then a bitmap image should be no better than 180ppi. The 4:1 ratio gives the RIP a 4x4 matrix of printer dots with which to dither the color for each image pixel. That would be at least 5^16 [5=CMYK and the white of the media itself] possible color combinations for each image pixel.

I find that a 150ppi image printed at 720dpi is, for the most part, flawless. At these the edges of objects in bitmaps cannot be told from the edges of vector objects resolutions.

Moreover, I always send RGB, never ever CMYK bitmaps with a bitmap rendering intent of 'Perceptual'. The 4:1 image ratio yields pretty much a what you see is what you get environment. Curiously enough I send all other elements as CMYK with rendering intents of 'No Color Correction'. Which does require the use of a pre-printed color chart but has the charm of producing utterly predictable and repeatable results.

 

[ahgrafx]

Thanks for all the replies everyone. I am new to this position here at work and am just using the same settings the past designer used. The rip software is on an ancient pc that is terribly slow so the smaller the files the faster they rip so that is why I was told to use JPEGs. We dont accept pdf files here so I have to make a pdf file of the .ai then open in photoshop and jpeg it to print at 12 quality. The image on the screen doesnt show the antialiasing problem it only appears when it is printed.

 

[ahgrafx]

I dont ever send RGB images because they always are darker when printed.

 

[ahgrafx]

im printing at 720

 

[GAC05]

Can you post up a cropped section of the jpg that shows the issue?
It looks almost like the kind of glitch I get when the encoder strip is dirty, but mine runs all the way across scan width.
Do the outer edges of the black background show a similar defect in line with the problems on the curved letters?

wayne k
guam usa

 

[ahgrafx]

Can you post up a cropped section of the jpg that shows the issue?
It looks almost like the kind of glitch I get when the encoder strip is dirty, but mine runs all the way across scan width.
Do the outer edges of the black background show a similar defect in line with the problems on the curved letters?

wayne k
guam usa

it does go all the way across the banner on that same line. How do you clean the encoder strip? I posted a jpg in the original post or are you talking about the print file?

 

[Snydo]

Drive down the street to Microsoft and look in the dumpster for PC parts. Seriously though, tell/ask the boss to upgrade the RIP computer.

 

[GAC05]

I'm not totally sold on it being the encoder.
Usually it is terminal error as the head looses it's place it does not get back on track & the printer shuts down without finishing the print.
Maybe the 1624 has some self correcting built in that pulls it back on line but who knows, mine is a 1304.
Anyway the encoder strip runs horizontally along rails - it is a clear plastic strip about 1/2 wide.
You clean it with a little alcohol (don't use the solvent cleaning fluid) on one of the lint free patches that come in the cleaning kit.
You need to be a little gentle and not bend, fold, staple or mutilate it.
If you get a lot of ink residue off the strip you might also want to clean the sensor.
It should be on the right side of the carriage behind a plastic cover. Mine has a single screw holding it down - remove it and use the alcohol pad wrapped around the edge of credit card to clean it out.
The sensor that controls the feed is on the left end under the end cap. It looks like a clear CD. This one does not get exposed to much ink mist but you may want to clean it too.
Someone here has the service manual for the 1624 that will show an exploded view of your printer (I only have the earlier 12 13 and 1604 versions).
Quick search will pop him up.

wayne k
guam usa

 

[ahgrafx]

Drive down the street to Microsoft and look in the dumpster for PC parts. Seriously though, tell/ask the boss to upgrade the RIP computer.

I know what ya mean snydo i could throw a rock and hit microsoft lol I guess this pc is an upgrade from before I came here.

 

[ahgrafx]

I'm not totally sold on it being the encoder.
Usually it is terminal error as the head looses it's place it does not get back on track & the printer shuts down without finishing the print.
Maybe the 1624 has some self correcting built in that pulls it back on line but who knows, mine is a 1304.
Anyway the encoder strip runs horizontally along rails - it is a clear plastic strip about 1/2 wide.
You clean it with a little alcohol (don't use the solvent cleaning fluid) on one of the lint free patches that come in the cleaning kit.
You need to be a little gentle and not bend, fold, staple or mutilate it.
If you get a lot of ink residue off the strip you might also want to clean the sensor.
It should be on the right side of the carriage behind a plastic cover. Mine has a single screw holding it down - remove it and use the alcohol pad wrapped around the edge of credit card to clean it out.
The sensor that controls the feed is on the left end under the end cap. It looks like a clear CD. This one does not get exposed to much ink mist but you may want to clean it too.
Someone here has the service manual for the 1624 that will show an exploded view of your printer (I only have the earlier 12 13 and 1604 versions).
Quick search will pop him up.

wayne k
guam usa

I cleaned the Tfence/encoder there was a big black mark on it like someone had scribbled on it with a permanent marker (maybe that was the problem?) but i got it off so maybe that will help, havent had the opportunity to run a test yet.

 

[ahgrafx]

mine doesnt seem to be a clear plastic strip it seems to be thin metal, hope I cleaned the right thing

 

[Biker Scout]

Yeah, pretty sure you have one of these

 

[ahgrafx]

looks like I cleaned the wrong one, but them found the correct one and cleaned it but it is still doing it.