[w i l l]

Yeah but this billboard is 240 x 480 inches. Pretty big!

[simmsimaging]

Another option is to find a service bureau with a film recorder and shoot a piece of film from your digital file. That can then be scanned to whatever final res you want/need. We used to do this all the time in the old days when our desktops couldn't handle the larger files. Works fine but it adds some cost/steps to the process.

b

[w i l l]

Would that be less costly than using a render service? Do you have any experience with companies like 'renderrocket.com' for example?

[simmsimaging]

Sorry - no idea on that front. I have never used a render service. In my neck of the woods an 8X10" film output runs around $200 CAD, and the scan will depend on how big you go and who does it - but probably in the range of $200-300 at a guess.

b

[w i l l]

Yeah i might just have to give the company that option. They did originally say to me A3 size at 300 dpi which is just over 3000x3000 pixels.

If i rendered at 1500 x 1500 would alien skin do an alright job at blowing up to 200%?

[simmsimaging]

for 200% enlargements Alien Skin is more than fine.
b

[w i l l]

Ok cool. Thanks, i'll give it a go.

[w i l l]

Rendering at a higher res then downsizing the image really helps with noise problems... i never expected it to make so much difference. I think i'll probably render everything at as high a res as possible from now on.

[KurtS]

Rendering at a higher res then downsizing the image really helps with noise problems... i never expected it to make so much difference. I think i'll probably render everything at as high a res as possible from now on.

Yes,

If Pawel would render at 24.000 x 18.000 he would probably have it noise free already at SL 16!

[Pawel Kruk]

I'm glad this topic is evolving.

simmsimaging:
Sounds interesting.
Now I remember we also used to make a copy of a regular render on the photopaper (kingsize) for our competition projects and it works great too. Definately need to check on that.

1. About the dpi I'm still confused. Native MR render are 72 dpi, right? Than, do you artificially "add" dpi in PS? or you downsize the render to get 300dpi and after that blow it up again?
2. From user POV, regarding the noise - is it better to render one shot to higher SL, or make two with different seed value and lower SL and merge'em after?

Thanks

[Mihai]

When rendering, dpi is irrelevant. A 100 pixel image at 300 dpi has the same amount of pixels as a 100 pixels 72dpi image. You can change the dpi specified in the file (so the printer knows what dpi you want it printed at), by going to image size and unchecking Resample Image (in Photoshop). This way you can just adjust the dpi without changing the amount of pixels in the image.

Before rendering, you can figure out at what resolution to render by knowing which dpi you will be printing at.

[simmsimaging]

1. About the dpi I'm still confused. Native MR render are 72 dpi, right? Than, do you artificially "add" dpi in PS? or you downsize the render to get 300dpi and after that blow it up again?

Very common area of confusion. The main thing to remember is that DPI isn't really a measurement of actual image size/resolution: it's a measurement of pixel distribution. The render size you set in Maxwell, or anywhere else, determines your file resolution (i.e 1200X1200 pixels). Your DPI is just a matter of how close or far apart those 1200 pixels will be spaced when printed or displayed.

Closer/tighter spacing creates the visual impression of continuous tone images, and 300 DPI is a conventional standard for printing something that looks continuous. Your monitor is probably 72 DPI and can achieve that impression with far less pixels.

In order to fill the same amount of *physical space* (i.e 4" of paper or screen or whatever) with pixels/dots that are more tightly packed together (like 300 dpi instead of 72 dpi) then you'll need a lot more of them to do the job; so you need higher res images because they actually have more pixels in them (2000X2000 pixels instead of 1200x1200 etc). That's why it's common to refer to 300 DPI files as "higher res" than 72 DPI files, even though the measurement of DPI has nothing to do with how big the file actually is. That said, the DPI is always *derived* from the actual pixel size of your file. DPI is only part of the info though, it's always connected to a physical size and without that it's largely meaningless.

So - nutshell is you set your resolution and size by actual pixel dimensions and the DPI you adjust to the final display requirements.

That help?

b

[Pawel Kruk]

Got it! (I think)
Thanks for explaination.

[wimver]

Pawel,

there is a relation between resolution and viewing distance. The larger the image, the further away you stand to view it. here is a good explanation about this:

http://www.signindustry.com/outdoor/art ... tance.php3

here is another good one:

http://www.northlight-images.co.uk/arti ... tance.html

furthermore, since you mentioned that it will be printed on textile, the resolution can be reduced since the "resolution" of the textile weave is much coarser than what can be printed on paper.

hope this helps.

Wim

[Pawel Kruk]

That's a really good reading wimver, thanks for the links.
I've seen how they print textile banner before and I would be surprised if there is more than 75dpi they use, but they always ask for higher quality materials eventhough it will be downgrade before printing. From the other hand client have no idea how this works and trust more printer than you, so those articles might be good argument when talking with both. Thanks again.