Print Quality Issues

[phenomenal]

Hi everybody.

I'm having a problem with my vray renders, after the render has been completed (all set to the correct resoloution settings, with vray materials and what I believe to be good IR/LC settings) the renders look great.

BUT

when I print them at uni the result looks quite different. Sometimes I get a weird radial effect coming from certain objects, also there seems to be a massive drop in sharpness on some renders. There seems to be no logical reason for this, occasionally I have had a render which printed well, which used the same model, materials and settings as the ones that haven't (which is the majority).

I have even used the ASGVIS vray print quality VISOPT and had the same problem.

I normally save as png, then do some work with the image in illustrator. I tried today to save a variety of formats straightout of vray and print with no adobe use, same problem.

I can't find anything related to this in any forum searches so if you had any advice I would be very grateful.

[fooprobe]

Re: Print Quality Issues

if it looks good on screen but prints badly, sounds like a printer calibration issue. are you changing the color mode of the images to CMYK before you print? any chance you can post the image and then a scan or pic of the print so we can see the effect?

[arqestevez1]

Re: Print Quality Issues

you also need a good screen, cause i've seen that my renders look different in other pc's... at the office i have a smaller pc, and for example, i try not to make any photoshop corrections, because i do not notice small changes... in this case, it does seem to be a printer issue, but are you sure that those radial effects are not in your renders before you print them?
i've realized that those things appear when we use too much post production, or when we change a lot the shadows and highlights

[fooprobe]

Re: Print Quality Issues

there's also a known issue with the way v-ray handles gradients, it produces a color banding that can be more or less noticeable depending on your lighting quality settings. there are a few threads on this, but this one is pretty clear and pretty recent:

http://forum.asgvis.com/index.php?topic=9016.0

if this is what's going on, you have to fix it in photoshop

[phenomenal]

Re: Print Quality Issues

Hi

Thanks for the replies, both of my computers have good screens, but i don't this is a screen problem.

I can't seem to attach files, so here is a jpeg of the render:

http://i53.tinypic.com/250rn1v.jpg

and here is a photo of the printed render I just took, awkard angle but it shows one of the problems I am getting, strange radial discolouration.

http://i51.tinypic.com/izaiix.jpg

It almost looks as if some liquid has been spilt on the actual print, you can just make it out in the photo, in reality it is even more visible than this.

[fooprobe]

Re: Print Quality Issues

your first link is broken. here's how you post images:
http://forum.asgvis.com/index.php?topic=2043.0

looks like it might be the color banding issue i mentioned in my last post. make sure you're saving in a 16-bit format and check to make sure you convert to CMYK before you print, that can cause banding too.

[phenomenal]

Re: Print Quality Issues



seems to be working for me.

OK, PNG is a 16 bit format yes? And a lot of my work goes straight into illustrator for layout, which works in CMYK

I see the problem in the other thread looks similar, but how can this be stopped in Vray? Or does it have to be fixed in photoshop for each render?

Thanks

[fooprobe]

Re: Print Quality Issues

sorry, just my browser being goofy.

when i open your jpeg, i see the same color banding on screen.

png has a 16 bit option, but v-ray saves it as 8-bit. i would try saving it out of v-ray as HDR or targa, then converting to 16-bit PNG in PS (or just use the targa in AI)

but more generally, i don't think there's a fix, other than to blur this in PS. someone, please correct me.

[phenomenal]

Re: Print Quality Issues

when I save files as hdr I get a very washed out look, nothing like the above, which was originally a png before this forum.

[phenomenal]

Re: Print Quality Issues

and yes your right, the banding is visible in that file, but only after conversion to jpeg.

[fooprobe]

Re: Print Quality Issues

even targa is only saved as 8-bit from v-ray. use hdr. hdr is saved with linear gamma. open the hdr in PS and go to image->adjust->exposure, set the gamma to 0.45454545, it will no longer be washed out.


post the original PNG?

[phenomenal]

Re: Print Quality Issues

I can post the original tomorrow, it's on my desktop at home.

Would this approach stop problems I've had with other files? Such as loss of quality? And very punchy and sharp screen renders printing dull and forgettable?

[fooprobe]

Re: Print Quality Issues

hard to say. what kind of quality loss? saving as hdr gives you a lot of post-process control, so you should be able to punch up renders easier with it. but do these issues occur with other images (e.g. digital photos) that look good on screen but not when you print? an awful lot of this depends on your printer quality, printer calibration, your paper quality, etc. it's not as likely to be a v-ray problem.

[phenomenal]

Re: Print Quality Issues

Its just a vray problem. The uni printers are pretty decent, and there in an architectural printing studio so they are set up correctly, or at least they should be.

But yeah, all my photos, and other work print completely fine.

The loss of vray quality generally involves a loss of sharpness, and a loss of punch from the images.

[fooprobe]

Re: Print Quality Issues

Weird. Once an image is in ps or ai or whatever, it shouldn't matter where it came from... It should print like any other image.... No clue.