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Poser - OFFICIAL F.A.Q (Last Updated: 2024 Nov 21 6:06 am)



Subject: Rendering in Poser 7


Vampi ( ) posted Wed, 05 September 2007 at 10:43 PM · edited Sun, 24 November 2024 at 4:56 AM

I'm having a problem. I can render and export in any format at .300 dpi, except for .png. I like using the .png format because it leaves just the figure and not the background, but when I export as a .png file, it saves it at .118 dpi and when I resize it to .300 dpi, it's only half the size. 

I've posted in a few places, but I'm not finding anyone else who has the problem. Any suggestions?


Miss Nancy ( ) posted Wed, 05 September 2007 at 10:57 PM

render png at 72 dpi and desired pixel dimensions, convert to 300 dpi for printing in APS/PSP.



Vampi ( ) posted Wed, 05 September 2007 at 11:02 PM

If I render at 72 and want my picture to end up being 10 inches tall, then I just render it at that size and resolution?


Vampi ( ) posted Wed, 05 September 2007 at 11:15 PM

I tried it your way and it downsized it to 28 dpi and again, half the desired size sigh I'm not getting anywhere with this program. I'd go back completely to Poser 5 except it doesn't work as well with V4 and all her stuff.


Miss Nancy ( ) posted Wed, 05 September 2007 at 11:41 PM

no, wrong, vamp. e.g., desired print size = 8 in. X 10 in. render at 72 dpi and 2400 X 3000 pixels. in APS/PSP, convert to 300 dpi and 2400 X 3000 pixels. e-f were sposeta fix this bug long ago, so that one could render at any desired resolution in poser. it's just sad if they still haven't fixed it IMVHO.



Vampi ( ) posted Wed, 05 September 2007 at 11:59 PM

I tried your suggestion and it still downsizes it to 3 inches tall, instead of the 10 at 300 dpi. Instead of saving the 72dpi that I wanted it rendered at, it rendered it at the desired dimensions, but at 28 dpi. This is nuts.


cspear ( ) posted Thu, 06 September 2007 at 12:00 PM

file_387156.jpg

Vampi,

it's not nuts, you just haven't got your head round the required concepts.

Are you using Poser 7 with the latest service pack? These problems seem to have been fixed in that.

These screenshots show how I set up render dimensions in P7, and how the resultant render, saved as a PNG, came out as expected in Photoshop.

If it's not working for you like that, you should:

(a) figure out how many pixels should be in your render - e.g. a 10in x 8in image at 300 ppi (pixels per inch) needs to have 3000 x 2400 pixels - and set that as your render dimensions in Poser. I always work in pixels, not inches or centimetres.

(b) in Photoshop, turn resampling OFF and set the resolution to 300 pixels / inch. And make sure it's not working in pixels / cm, because it sometimes does that if it's preferences get trashed.


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bagginsbill ( ) posted Thu, 06 September 2007 at 3:45 PM

file_387181.jpg

What is all this fascination with PPI about? I don't get it.

When I want to print a picture, I open it in photoshop and choose Print Options. I then type in the exact size in inches that I want. The actual number of pixels has no impact on the printed size, nor does the PPI or DPI or whatever stored in the image.

In the screen shot, I'm showing that I've asked Photoshop to print my image 7 inches by 7 inches. How many pixels does it have? I don't even know. What is the PPI? I don't care. It works all the time.


Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)


FrankT ( ) posted Thu, 06 September 2007 at 4:04 PM · edited Thu, 06 September 2007 at 4:04 PM

You aren't a digital photographer then I take it BB ? :)

We agonize over every single pixel that comes off the camera.  If you think about it, a 10x8 image at 72 dpi straight out of the render engine doesn't have anywhere near enough pixels in it to print 10x8 at 300 dpi which is the standard for printing.  Photoshop can create extra pixels to fill in the gaps but it's never going to look as good as if you have enough pixels in there to start off with.

Why'd you think PhaseOne digital backs give you 45 megapixel or higher images ?

It's always better to throw pixels away than not have enough

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Arien ( ) posted Thu, 06 September 2007 at 4:16 PM

Bagginsbill: no, it doesn't work if you're creating work to go into a professional printer. If you render  a 600x800 pixels image, and you send that to a printer to go into your Christmas Cards that are sized 5"x7 1/2", the printer will send it back after he stops laughing. What photoshop is doing in that image of yours is just resizing the image on the fly and bypassing the settings; but to generate the initial image size (the 100% size print) it will use the ppi value stored in the image itself unless you change it. For good quality printing you need at least 300ppi; for home usage you might get away with 150 ppi but less than that and the image quality will suffer. When you've got very big images that are being sized down -as in your example- this doesn't matter too much, but it's critical if it's the other way round.  Also, your method of resizing on the fly is also bypassing adjustments that might be necessary when resizing images to get the better results.

Vampi: try what everybody else is telling you. Render at the desired and correct pixel size, save, and change the ppi in a paint program, without altering the actual pixel size. That's what I do for the pieces for print I make.

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Vampi ( ) posted Thu, 06 September 2007 at 8:41 PM

Yep, I've installed the latest service pack. I've tried doubling the size of the render for png file format, but I get a warning that it'll take too much time, so I scrubbed that. I'm getting really sick of these problems when I've spent so much bloody money on the program sigh

Someone did mention before, though, that they can be saved as .tiff files and then do something with the alpha channels.... I don't understand how that works, so I guess I'm going to have to figure it out.

Thanks everyone :)


Arien ( ) posted Fri, 07 September 2007 at 2:37 AM

Save as a TIFF, then in Photoshop, go to the channels palette, there should be an Alpha Channel that you can use as a selection to then extract your figure from the background. Works pretty much the same.

Although wait a minute... you are saying the program did render at the "desired dimensions", just at 28ppi. Can you PLEASE show here:

1- a screenshot of your render dimensions dialogue
2- a screenshot of the sizing/ppi information from Photoshop

Otherwise it is very difficult to explain things to you.

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bagginsbill ( ) posted Fri, 07 September 2007 at 7:54 AM

I seem, once again, to have not been clear about my point.

If I want a 300 PPI 8 x 10 render, I would set my render dimensions to 2400 x 3000 pixels. Whether or not the "pixels per inch" value goes into the file at 300, 200, 343534, or 1, the image is still, without a doubt, consisting of 2400 pixels by 3000 pixels. I'm not suggesting I render at 80 by 100 and try to blow that up to 8 x 10 inches. I'm saying that the image attribute stored in the file, which we call PPI, does not have any impact on the printed SIZE because I get to say what size I want in photoshop. If I size it to 4 x 5 inches instead, it will actually print at 600 PPI, even though the file says 300 PPI or 20 PPI or 800343534 PPI.

So it does not matter if Poser fights with you and LIES about your specific PPI in the file attribute after you store it. That number is just a suggestion about how big to print it, and if its wrong, you just change the print size in the Print Options. I agree that if Poser did NOT lie and did indeed put a 300 into the file attribute PPI value, then you could just Print straight away without having to correct the final size.

Similarly, if you decided that you wanted to print a poster at 16 by 20 and you were willing to accept that this will be 150 PPI instead of 300 PPI, there is no reason to go back into Poser and try to render the image over again. The final pixels will be the same whether you told Poser to render 8 X 10 inches at 300 PPI or 16 x 20 inches at 150 PPI. Makes no difference.

In case I'm still not clear, I'm saying that I understand WHY you want higher pixel density and I DO photograph at the highest resolution possible on my digital camera. But I don't need to edit the image PPI value to make it a particular size. I just choose the size, and the printed resolution will be what it will be. Similarly, when I render, I render at the highest resolution I'm willing to tolerate (in terms of render time) and then I pick what size to print at the very end.


Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)


Arien ( ) posted Fri, 07 September 2007 at 8:12 AM

BB: ok, but there is still the minor issue that if you are using that image for submission to a printer, printing services or to other programs like InDesign, you WILL need to have the PPI/DPI set up properly to indicate the real size it needs to be printed at.  I think we've all suggested the OP to do what you outlined above, but if I gather what she's saying correctly, despite setting the pixel size correctly, she is still having smaller images than required as a result, or is somehow unable to change it in her 2D program.

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bagginsbill ( ) posted Fri, 07 September 2007 at 9:30 AM

file_387240.png

Did a little research. To the best of my knowledge, the PNG file format does not contain an attribute for pixels per inch or dots per inch. Maybe this is because PNG was specifically designed for viewing on a computer as is (no scaling), in which case PPI is not relevent.

Because the operating system (at least mine) claims the screen is 72 PPI, when I load a PNG file into photoshop it reports it to be 72 PPI. I created a 2 inch by 3 inch 300 PPI render and saved it from P7. Loading into Photoshop, it claims it is 72 PPI, and therefore will print to 8.333 inches by 12.5 inches. Vampi's computer must think that the screen is 118 PPI.

In any case, with Photoshop this is easy to fix. Select Image/Image Size - this brings up the Image Size dialog. Turn off the Resample Image checkbox. Then change the "Resolution" to 300. Voila - the original 2 by 3 inches is now restored. Asking it to print now will produce a 2 by 3 inch print. 

BUT!! Saving the file with the modified PPI and then sending it to a print shop will do no good. The 300 PPI value is lost as there is no place to write this information into a PNG file.

So anybody who is sending PNG files to a print shop thinking they are going to know what size it is supposed to be is asking for trouble.


Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)


bagginsbill ( ) posted Fri, 07 September 2007 at 9:40 AM · edited Fri, 07 September 2007 at 9:40 AM

Heheh,  more research, more info. Apparently PNG files can contain additional information that is invented over time. Photoshop 6 did not know the PPI, but Photoshop CS2 DID!!!!

So when I rendered the same scene both 600 x 900 pixles, but one at 300 PPI the other at 145 PPI (just to pick a strange number), and load those into CS2, it correctly knows the different densities.

Upgrade your software. It seems that Poser 7 knows what to say in the PNG file and that Photoshop CS2 also knows.

And I did hear about PPI/DPI bugs in earlier releases of Poser 7 - make sure you have the latest service release. It appears to work correctly. I'm using Poser 7 version 7.0.2.131


Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)


bagginsbill ( ) posted Fri, 07 September 2007 at 9:52 AM

I've confirmed that the information is in the PNG file just fine.

I examined the raw binary data in my two files.

I found a place where the 145 PPI file had the number 5709 and the 300 PPI file had the number 11812. Turns out that 145 pixels per inch is 5709 pixels per meter, and 300 pixels per inch is 11812 pixels per meter. So the PNG file has the density stored in pixels per meter precisely.


Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)


bagginsbill ( ) posted Fri, 07 September 2007 at 10:02 AM · edited Fri, 07 September 2007 at 10:03 AM

Previously I had been Googling for "PNG pixels per inch" and found nothing. But with the clue that the data was in meters, Googling for "PNG pixels per meter" yielded this:

Earlier Adobe versions (prior to Photoshop 7 or Elements 2.0) did not store or read the ppi number to scale print size in PNG files (Adobe previously treated PNG like GIF in this respect, indicated 72 ppi regardless). The ppi number never matters on the video screen or web, but it was a serious usability flaw for printing purposes. Without that stored ppi number, we must scale the image again every time we print it. If we understand this, it should be no big deal, and at home, we probably automatically do that anyway (digital cameras do the same thing with their JPG files). But sending a potentially unsized image to a commercial printer is a mistake, and so TIF files should be used in that regard.

Most other programs do store and use the correct scaled resolution value in PNG files. PNG stores resolution internally as pixels per meter, so when calculating back to pixels per inch, some programs may show excessive decimal digits, perhaps 299.999 ppi instead of 300 ppi (no big deal).


Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)


Vampi ( ) posted Fri, 07 September 2007 at 10:31 AM

Okay, here are the print screens in order:


Arien ( ) posted Fri, 07 September 2007 at 10:39 AM

Huh? Where's your problem? Your screen is showing 118.120 pixels per CENTIMETRE, which is 300 pixels per inch, exactly what you have above in your Poser settings.

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Miss Nancy ( ) posted Fri, 07 September 2007 at 12:39 PM

it also has "resample" checked. never resample when changing dpi. maybe this problem would be better handled by the photoshop forum. it is well within their expertise IMVHO.



Arien ( ) posted Fri, 07 September 2007 at 12:58 PM · edited Fri, 07 September 2007 at 1:00 PM

Miss Nancy: there is no problem. The only issue is that Vampi is reading the resolution that is stated as pixels per cm as pixels per inch. 118ppc = 300dpi. Everything is fine, nothing needs to be done.

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Vampi ( ) posted Fri, 07 September 2007 at 5:22 PM

Yeah, Deviant Bunny is right :) I found out where the problem was, smacked myself in the noggin for being a doofus and came here to thank everyone for responding and giving me advice on this :)


Arien ( ) posted Fri, 07 September 2007 at 5:37 PM

You're welcome, Vampi :)

Happens to the best of us. Hope it's all sorted now.

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