Dots per inch, Printing

unhandled

#1

I’m trying to print (selection) a tiff image at 300 dots per inch but the resulting image keeps coming out at 72 dpi. Please fix this !


#2

Just render it out at the number of pixels you need for 300dpi, the “dpi” setting is just a value set in the file that is basically irrelevant to printing it via Photoshop or putting it in an InDesign document or whatever.


#3

line drawings???


#4

What are you actually trying to do and how?


#5

Cayenne It would help if you were more civil in your posts. You need to let us know exactly what your trying to do, also if you post you file it helps.


#6


(Jakob Normand) #7

Hi @Cayenne

I have no idea as to why our picture comes out 6000x4500 pixels, when the screenshot of your print settings say it should be square… but… as for the resolution, it’s spot on. Your picture size says 6000 px wide. 6000 pixels printed in 300 dpi (dots per inch) is exactly 20 inches. The dpi setting is not important, as this number will change if/when the picture is scaled (without being re-sampled in Photoshop or similar). So basically all that matters is the amount of pixels. Take your desired print size in inches multiplied by your desired print dpi (eg. 15 inches x 300 dpi) and presto, you have your render size: 4500 pixels.

HTH, Jakob

Edit: Here is a great explanation of the whole dpi/ppi thing…
http://www.rideau-info.com/photos/whatisdpi.html


#8

YES, Yes, Yes, I know all the “work arounds” the reason I posted here is I
don’t want to do the “work arounds” I want to print directly!!! It is
supposed to do this!!! Why is the exif data in the image always at 72dpi
when it should be 300???


(Jakob Normand) #9

Directly from what? Rhino, Windows, OSX, InDesign, Word, your smartphone, a webbrowser?


(Wim Dekeyser) #10

It’s not a work around. You want 300 dpi and 20 inches - you get 6000 px.


#11

GOOD GOD! When you print an image at native resolution it use the dpi number in the exif data! why is this so hard for people to understand??? I posted screen grabs that show it is not working properly!!! JUST FIX IT ALREADY!!!


(Steve Baer) #12

Hi Cayanne,
We actually don’t write any exif data to our image files so Windows is just making up a default number. What application are you using to print the image?


#13

I want to use rhino to print an image at the dpi “I” choose, copy this image to a thumb drive, insert thumb drive into my large format printer, print at 100% WAHLAH! my image prints correct size! with absolutely no post processing anything on my part!!! It is the EXIF data that tells the printer what the default dpi that the image is intended to be printed at! LOOK at the image properties in the second screen grab, it says 72dpi for this image this EXIF data should say 300 dpi!!! WHY does Rhino write
this exif data incorrectly??? WHY does it NOT write the dpi it asks me for??? which is 300???


#14

Then why does rhino ask??


(Pascal Golay) #15

Presumably so it can calculate the correct number of pixels so that you can print at that ppi.

-Pascal


(Steve Baer) #16

Everything in an image comes down to dots. The equation is
dot count wide = inches wide * dpi
dot count high = inches high * dpi

We also need DPI to determine how thick to draw curves based on their thickness value.


#17

Then what is the 1 to 1, and inches, and scale settings for ?


#18

THIS IS THE PROBLEM ! You mislead the user into thinking You are actually writing EXIF data and you are NOT! Well you are writing some of what you are collecting but NOT all you are collecting! CAN YOU FIX THIS???


#19

Write the dpi to the EXIF data please, for the love of GOD!


(Steve Baer) #20

This defines the scale from world units in your model to size on a piece of paper. (i.e. it most likely wouldn’t be 1 to 1 for modeling a skyscraper).

Not for V5 as we are done with service releases. Are you interested in figuring out a work around? I do agree that this can be improved, but it would have to be in a version of Rhino that is in active development.