Could some explain how to export a InkScape document and maintain the size (length and width) along with the DPI?

I come from a CorelDraw background and would like to use InkScape for cover design. What I want to do is design a cover that is 1600px (wide) x 2400px (high) at 300 DPI?

1. I use the default pixel template as a starting point.

2. Using Document Properties, I set the width at 1600 and the height at 2400 px. The Scale is set at 1.0 (I'm not sure what scale does but assume the default of 1.0 is reasonable).

3. Create my document, no problems here.

4. Here's where the problems come in. I select Export PNG.

5. I don't understand the Export Settings and the relationship between Page size and Image Size? I've selected "Page" as the export area since I'm trying to export the full document.

6. I set the width and height to 1600 x 2400. When I do this, the image size shifts to 3226 x 4838 pixels at 193.54 DPI but I wanted 1600x2400 @ 300 DPI?

7. Do you have to set the Image size or Page size or both?

8. If I reset the DPI to 300, my image size goes to 5000 x 7500? If I change the width, then the DPI drops to 96 DPI. Why does the DPI and output size change?

9. What am I doing wrong here?

10. I'm assuming that the goal of InkScape is to be able to perform the same type of operations as CorelDraw. The layout and general operation seems remarkably similar. When you are creating an ad or cover, you need to be able to generate a precise size at high resolution so that the output looks good. I'm using the 1.1 development version, which is improved over 1.0 but still seems to miss the mark? If someone could give me a more detailed explanation of how to export and maintain size and resolution, I'd be greatly appreciative.

You can force physical dpi in the advanced PNG export settings.  

I'd keep the "Image Size" dpi at 96 and set the advanced "pHYs dpi" at 300.  The exported PNG opens in GIMP at 1600x2400 300dpi.

As for trying to be like other illustration programs... meh. Trying to be a great illustration program, of course.

Thanks for the help. Is there any explanation of what the various items in the export are mean?

I set the Image Size to 1600x2400 and let the DPI go to 96. Then I set the pHYs at 300. The export .png looks fine. Thank You.

Do I need to set the image size or can I just lock the pHYs at 300 and export whatever size pops up?

"Trying to be a great illustration program, of course."

Now that I've mostly solved my problems with InkScape, I'm going to recommend it to other writers that I know for use in creating covers. 

lylem

Do I need to set the image size...

I would. I just tested and the image size affects the output regardless of the pHYs dpi setting.

Thanks for all the help. The pHYs setting solved the problems and now my output is as desired. I think the export dialog box is confusing and don't understand why it works the way it does? I'm not sure who the audience was when InkScape was conceived but if it is aimed towards people creating ads, posters, or book covers the current default doesn't hit the mark. You need to be able to easily generate a specific size output at high resolution and while InkScape can do that, it is not intuitively obvious to the casual observer as my Diffy Q professor used to say.

As a software designer in a past life, I'd recommend that technical writers should review the program's operation and not the coders. When you are intimately familiar with a package that you wrote, little things like the output DPI should be handled differently. I was on a team which developed CBT software and it was the most educational job I ever had. I learned so much from our technical writers and production people to fold into my software. It's like the common saying, programmers should never write the help manual. LOL

The forced dpi is new. It was previously locked to the image size. (You have arrived at a good time.)

Keep in mind the Inkscape dev team is tiny ( a handful of regulars) compared to the armies of folks working on projects like GIMP, Scribus, Blender, etc. They probably would love to have assistance with documentation and user-guides.

Inkscape is a project to leverage the enormous potential of the native SVG file format, and as such, is a remarkable FOSS tool for illustration within those constraints.

Most of what drives new users to Inkscape is the cost of Illustrator and Corel and/or the cost of systems to run them. Inkscape can do most of what non-professional users of those programs need. It can do much more as well, for special applications outside of conventional graphic design; so some users gravitate to Inkscape because traditional illustration programs can't fill the special needs.

TD

Sorry, didn't mean my post to come across as a bitch session. I'm amazed at how good the program is and appreciate that it is a labor of love. I've been trying to switch everything to open-source software myself. GIMP, Lazarus, and InkScape are decent replacements for the high priced options.

Before I learned how to lock the size, I found that I could simply open the InkScape file in GIMP and export from there but that entailed another step.

Keep up the great work and I've donated $50 to your coffee fund.

I love coffee.

But I'm not a developer, but an end-user like yourself.  I salute your contribution to the cause. It will support the next hackfest, once it's safe to travel and get together again. 

Much appreciated.😀

Tyler Durden, regarding your answer above about the pHYs DPI to 300, does this mean that if it's set then any image size I choose to export will result in a DPI of 300 (or whichever number it's set to)?

MarcC

Tyler Durden, regarding your answer above about the pHYs DPI to 300, does this mean that if it's set then any image size I choose to export will result in a DPI of 300 (or whichever number it's set to)?

That's my understanding.

Thank you Tyler Durden.
How can I confirm the DPI of the exported PNG image?  I know I can see the size dimensions in pixels, but how do I confirm the DPI?

I usually open the png file in a program like Irfanview or Gimp, the look at the image info or image size.

Tyler Durden, I figured out a work-around.  I decreased the size of the image in Inkscape by using the arrows, then I was able to select an image size of 1500x2100 AND 300+ DPI.  
I still like the pHYs DPI setting idea better, more convenient, but it doesn't stay after being set, so I might as well just remember to decrease the physical size of the graphic and export at a larger size.
Thank you again for your assistance. I will play with pHYs and check in Gimp.

I was struggling with the same problem and i just try some math and that work for me. 

Normal DPI is 96 and we want 300. 

Multiply by 96 and divide by 300

1600 * 96 / 300 = 512

So 512px at 96 DPI will become 1600px at 300 DPI

Any way to force the pHYs DPI values on command line?