ZBrushCentral

Help please with DPI resolution problem!!

Community
#1

Hi folks, I am attempting to prepare a picture for printing by an outside source. The image is for a calendar and I am running into some problems.

I am having a little
problem with with dpi resolution v.s. height & width in inches. I will try
an explain it hopefully so that it makes some sense.

Firstly I am using Photoshop to save the image. The size of the image needs
to be 12.5 in. by 12.5 in. finished physical size, and the dpi resolution
needs to be 350 or better in .tif format.

OK so I created the image in Zbrush to be
1800 pixels by 1800 pixels so that when I took it down to AAhalf, it would
be 900 by 900 which is 12.5 by 12.5 inches at 72dpi. When I increase the
resolution to 350dpi the image enlarges to 4375 x 4375 pixels but still says
width & height are 12.5 x 12.5 inc. Yet the image on the screen is at least
double those physical dimensions. When I put the ruler on to measure it
looks like each inch shown on the ruler is actually 2 inches in real size.
And of course the image is not sharp and certainly not acceptable because
now it is oversized!

How can I overcome this? I can’t do the original in 4375 x 4375 pixels
because Zbrush won’t produce a document that large.

Any help with this would be greatly appreciated.

Thanks
Donna

#2

Sorry northstarr but thats exactly whats supposed to happen. You have gone from 72 dots per inch (hence dpi) to 350 DPI. So, 350 dpi X 12.5 inches equals 4375. PS increased the resolution yet maintained physical size. Thats what it does…but I bet you notice the image getting blurry. This is due to ps interpolating between pixols to make up for it. Creating about 2.5 times the pixoels. Yurning 1 into 4 (can’t have a half pixel).

#3

This is also a limit in zbrush yet a test of skill in photoshop. No offense to pixologic or anyone but I have been down that route many a time and its frustrating. But with some soft, selective blur brushing and a couple small hits of unsharpen masking, it will look better.
With my sysstem, there is no way I can have 16 layers (more like 6) at anything bigger than 2200 square in ZBrush.

#4

Yeh, what you said is what I was afraid of. One more question though, if I had a printer large enough to print this document, what size would it come out? 12.5 in. square or 25 in. square? Because if it comes out 25 in. square then I could reduce it by half and it would print the correct size. Right?

Donna

#5

Hi Northstarr

This is a link to a post by Aurick about scaling images (last paragraph). This was before the time of AA half in ZBrush but might still serve well.

It’s worth a try anyway I guess.

#6

hello northstar… i have no real answer: I always render pictures at the maximum size of zbrush,export to photoshop,in pshop get the picture to 300 dpi, then divide the size by at less two… it works,in professional use… I never use the aa half; is it interesting? … friendly .M.

#7

THe link to Aurick’s explanation is pretty much what I would do. Start with a larger document size than you need (the bigger the better). As long as it’s a perfect square (in this case) dimensionally, then you can resize the measurments down while increasing the dpi and get what you want. I work in a print shop and always doing this. :wink: