How does one create a 300 dpi render?

TauAlphaC

How can I create a 300dpi render?  Thanks for any help.

mjc1016

You don't...

DPI is a 'print' setting and has nothing to do with rendering.  You set your render to the pixel size you want and let the printing software worry about the dpi.  A 1500 x 1800 would, with the proper settings when printed, yield a 5 x 6 inch print.

nicstt

You calculate the resolution you need for 300dip, in relation to print size. IIRC, Blender has such a functionality built in.

Richard Haseltine

You can type

size in inches * 300

in the size boxes in Render Settings. A Daz Studio render doesn't have a PPI, the field isn't set in the image header (which is all it is - just a number setting the print size of the pixels).

TauAlphaC

Thank you all.  I am trying to create illustrations for a book, and I need them rendered at 300 dpi.  Still a newbie to DAZ, so appreciate the help.

SixDs

"I need them rendered at 300 dpi"

No. As mjc said, rendering isn't done in dpi. Rendering produces images in pixels, not dots. Photography produces images in pixels, not dots. The more pixels, the larger the physical size of the image in realworld units (inches, cm, etc.). When rendering you can specify the image dimensions in pixels (width and height). Regardless of the size or resolution of the rendered image, it can be printed at any specified dpi as long as the quality and detail are sufficient. It can also be resized if necessary. So, your job is to produce the best quality images in the correct ratio of height and width to fit your publication so that the printer has the best material to work with. If your printer is telling you that they require images in certain dpi, something is wrong. Ask them what resolution they require or recommend. Just remember, you can always reduce the size or resolution in an image editor following rendering if you wish, but you cannot effectively increase the size or resolution of a rendered image without sacrificing quality.

fastbike1

@SixDs  "The more pixels, the larger the physical size of the image in realworld units (inches, cm, etc.). "

Also not true. Pixel density and image size are not related in any rigid sense. My camera produces images that are 4000 x 6000 pixels. I have produced images anywhere from 4"x6" to 17" x 22" with these files.

"but you cannot effectively increase the size or resolution of a rendered image without sacrificing quality."

While perhaps theoretically true, also not true in a perceptual sense. All of this "you must have an image of this many pixels to get as print of this size" is many years out of date.

SixDs

I don't want to get into a debate about it, fastbike, but pixel density and image size are related as they come out of your camera or a render. When you first open them in an image editor, the software does not immediately ask you for an image size, it determines that dependent upon default values which you can then adjust as you see fit. Perhaps I should have said "for any given pixel density, the more pixels, the larger the physical size of the image in realworld units (inches, cm, etc.), although this can be adjusted in an image editing program if desired". Relative to increasing the size of images in an image editor I said that it can be done, but is limited by quality issues at some point. It may or may not be true that algorithms for filling in the missing pixels have become more sophisticated, but you are still using trickery. The principle of always starting with a resolution appropriate to your purposes or higher is still as valid today as it ever was, since you will never sacrifice image quality scaling down. In fact, that is exactly what you are saying yourself when you point out that your camera captures images at 4000x6000 pixels and that you can scale from 4x6 to 17x22 without issue. You have a lot of wiggle room there with 24 million pixels to work with. Nobody is normally going to be producing renders that size.

ericjcant

Wow, what a bunch of useless techno babble for such a relatively simple and practical question.

So, let's just say that you need your image to be 8.5" x 11" at 300 DPI...
Here's how you do it.

1) In your drop down menus go to Render and choose Render Settings.

2) Your Editor tab (usually somewhere on the side of your main viewport window)  should now show Render Settings. 

3) On the bar that says Pixel Size, click the little unlock button (if it's locked)

4) On the bar that says Dimension Preset, click the drop down menu and choose Letter (or whatever paper size you need). When you do this, the bar that says Aspect Ratio will change (think of this as being your paper size as a relative height and width).

5)  Now in the Dimension Preset bar, use the same drop down menu, but this time choose Custom, which should be right at the top of the drop down. You will notice that this time the Aspect Ratio (or render area) stays the same, but now by choosing "custom" it will allow us to use our own pixel dimensions, which we will do next.

6) Now change the width and height in the Pixel Size bar to roughly around 2800 x 3600 if you are doing a letter size print (I'm guessing here, but this will be pretty close for 300 DPI for a letter size printed sheet). If you need a larger or smaller paper size you will need to adjust this number accordingly and maybe fool around with it a bit and check it in Photoshop after rendering.

So, there you go. That's basically it.

Richard Haseltine

As I said above, type width * 300 and height * 300 intpo the size boxes to get the exact size needed.

gederix

Render your image at 72dpi and resize it to 300 in an image editing program, making sure to turn off any resample image function when doing so.

Think of it like this - a 72dpi image 10 inches wide is 72x10= 720 pixels wide.

When resized to 300dpi 720/300=2.4 inches.

So make your image approximately 400% larger than the desired print size (4x2.4=almost 10).

Or do the math to be exact. Desired image size x 300 / 72.

 

 

 

 

 

Tobor

This issue wouldn't keep coming up if D|S simply had a resolution setting as part of the render defaults, and stored that DPI/PPI with the file. This is how Poser works, and few of its users are confused by it. DPI/PPI resolution is an expected setting in all graphics programs.

While it's true you can simply render to the *pixel dimensions* you want, it also means that if you are making art that needs to have a DPI/PPI setting in the file (so things like printers know what to make of it), you have to manually open every single file you create and change it. 

AlienRenders

The only files I know of that have a DPI setting is PNG and TIFF. If you want to set the DPI tags, you can use a program like imageMagick.

convert -density 300 -units pixelperinch sourcefile.png outputfile.png

You still have to know what size to render your image at.

And this has NOTHING to do with DAZ or Poser. If Poser lets you set these values, then good for them. But if you don't know what you're doing when printing, complaining that the app doesn't do everything for you isn't going to help you. Realistically, these settings shouldn't be in the file anyhow. Printing hardware can automatically detect trim marks. If your image doesn't cover the entire page, then use something like PDF. And neither DAZ nor Poser properly handles colour profiles (aka colour management).

 

JD_Mortal

(DPI) is a "printer" setting, handled at "printing time". Though, some programs allow you to set this in an image. It has absolutely nothing to do with pixels at all, but it is commonly used to determine/portray pixel-size in an image.

A printer prints many dots to create one color. You don't control the color of the dots, or the sizes, you only "imply" what color you want a spot to be. If your image is 300 DPI, and your printer is 300 DPI, it will not print that RGB color in one dot, it will take about nine dots in a grid of 3x3 or 16 dots (standard), in a grid of 4x4 to represent one "pixel" of color. However, if printing in black and white, you will fire an individual "black" splotch of ink, as a single dot, only if the color is solid black. It uses that 4x4 pattern to "fake" shades of grey, by randomly printing dots or not printing dots, which you don't control.

However, most printers print with 1200 DPI, so thus, the 4x4 grid is 300 DPI (1200 / 300 = 4)... giving you some control over the output color, as actual pixels. (Most printers can only print CMYK, and 1-4 shades {dot-sizes}, to give the illusion of more colors.)

But, everyone should know how to calculate the desired "pixel size", to get that desired "print quality". That is, as stated, just the length (in inches), times the quality (DPI), which gives you a 1:1 quality of pixels to desired print output. (I am sure they siad this, because most programs default to screen PPI, and call it DPI which is 72 PPI. Plus, they don't want less pixels than required for that desired quality.)

However... You can have an image with 9808209823048092384 pixels, print at 300 DPI, when you set that value in the printer, or just scale the image to that inch-size. I am sure they were asking that the image be "at least" 300 DPI for print quality, not that it has to be exactly 300 DPI, which is rather low quality for print. Like I said, 1200 DPI is the standard for "production prints", to retain line-quality and also color-potential for RGB or CMYK conversions.

P.S. Almost every image can have the DPI or PPI setup. However, few programs save that info, and fewer programs know where to put that info, but almost every image format has a PPI/DPI setting designated for that value. They just use the "default value", which is 72, or NULL, which is also assumed to be 72. Even though they no longer make 72 PPI monitors and no longer use PPI for any real-world measurements.

Sorry, I worked for a 6-on-6 large-format printer... Plus, I program raw image data. It is habbit to chime-in, when I see a post like this. :P

Be glad they didn't tell you to render in Twips per pixel!

https://en.wikipedia.org/wiki/Twip

And the rest of the story...

http://www.andrewdaceyphotography.com/articles/dpi/

Fishtales

I found this years ago, it's worth a read.

http://www.scantips.com/no72dpi.html

All my images for the internet I save at 0 DPI, using IrfanView, or 1 DPI if using PS as it doesn't allow 0. If I save the image at 1000 pixels then, no matter the size of monitor it is viewed on, it will still only take up 1000 pixels, on a smaller screen it will need to be scrolled and on a larger one it will centre itself on the screen. Anyone trying to print it at 300 DPI will get a 3 inch image. When saving for print I save them at the finished image size multiplied by the print resolution. Some are 300 DPI but others might be as low as 150 DPI. The larger the finished print size the lower the resolution needed as the print will be viewed from farther way. Think of a 40'x20' billboard, the resolution for that might be 4 DPI but viewed from the street it looks fine, go up close enough though and you will see the dots but you wont see much of the image.

vonHobo

Richard Haseltine said:

As I said above, type width * 300 and height * 300 intpo the size boxes to get the exact size needed.

Thank you. That is a good way to determine this. It seems to match up with what my prints require for art poster output sizes.