Hi,

In this forum and elsewhere on the web, I found a couple of posts and FAQ's about this problem, but none of them helped me solve it.

I use a photo as the base of an graphic. I import the picture, embed it, clip a part out of it and combine it with some drawings created in Inkscape.
The result needs to be a (png) file with 200 dpi.

When I use the export function in Inkscape, the standard dpi is set to 90. When I increase that, the image size increases as well and that is not what I want.

How can I increase DPI size without the size of the images changes?

Thanks,
Ron

Welcome Ron!

Yes. I don't have a complete understanding of the issue, so I can only give a general explanation. But in Inkscape, the DPI in Export Bitmap dialog only changes the size. I realize that in raster graphics programs, the DPI affects the quality of the image. I guess in Inkscape, D= dots means the real pixels, which ultilmately can't change. The number of pixels on the screen can't change. Somehow DPI also relates to printing though, which I guess is how in raster graphics it's a measure of quality.

I've noticed several places in Inkscape where the terminology used is a bit questionable. Take Export Bitmap for example. That's confusing, and a lot of people, including me initially, thought it meant BMP. Imo, it should say Export Raster, because in the future, other raster formats will be exportable. So I don't know if Inkscape is using DPI slightly the wrong way, or in this case, maybe raster graphics uses DPI in slightly the wrong way.

I'm not sure how you can change the DPI without changing the size. Well, in Inkscape, you can't Maybe you could export it at the default 90 dpi, which will leave it the same size, then take it to a raster or even printing software to change the quality dpi.

Or someone else might have an idea (which I will hope to learn as well)

There is no way to change inkscape's default 90 dpi workplace.
To make embedding work well -considering the future exporting, you will have to save a copy of your yet to be embedded image of 90 dpi.
Then, when embedded, make its location match the pixel grid.
Preferably you should work with vector elements that match the image's scaling,
so that when exporting, you can use 90 dpi resolution.*
Yes, that's not 200, you will have to change that by another raster program that is capable of changing the dpi setting of an image.

*Other restriction on the exporting is to align the exprort area on the pixel grid as well.

I'm going to risk irritating someone by BTT'ing this with my first post because I've just run into this problem today and it's pretty annoying. Here's my try at a better description of the complaint:
Found in: Inkscape 0.48.4 and probably most other versions.
Problem: Cannot change DPI and Pixel size independently in the "Export Bitmap" dialog box.
Reason problem is happening: The physical size of the image being worked on is being treated as an inviolate word-of-god constant for the purposes of this dialog box and when DPI or dimension in Pixels is changed it is used to recalculate the other. This is completely counter-intuitive and arguably utterly-nonsensical behavior in the case of exporting to a bitmap format. The end result is that the source vector image needs to be altered for each and every export, or an outside program may be needed just to change the DPI of the image to fit the workflow. There should at least be a "preserve print size" checkbox or something here.

Hi.

You can set the base units and size of your document at the document's properties tab (Ctrl+Shift+D).
By setting it to a physical unit and saving your work to a pdf, you can have a size-accurate print.

There are printing devices that don't recognise any dpi setting saved with images.
With a vector pdf you can have a print with whatever dpi the printer can produce,
without the need of exporting to a pixel accurate raster image for that.

Actually the export raster image option is more for displaying the image on screen.
Where dpi doesn't make much sense.

I routinely create documents for commerical publishing that include both raster and vector content (I have to believe that many other users do as well). the raster (jpg images) must be enough resoultion (300-600dpi) to print cleanly (90 dpi isn't there). IS there any techniquie that would allow the creation of hte document without resizing the document by the ration of the required dpi over the fixed dpi (300dpi/90dpi)?
How could I contribute to adding a "raster effect" option like Adobe Illustrator (this seems like a very basic need for producing print documents)?

I'm not sure what do you mean.

By exporting to a pdf, mm/inch values are preserved right for printing.
You have a raster image embedded, you resize it to be exactly the size of their print dimensions in anything other than pixels, and you will have an exact match with your pdf prints in the term of the dimensions.

Raster based filters (-effects?) are rendered live through inkscape -causing slow downs in editing-,
which at a pdf export you can set the resolution how they should be rasterised.

This used to drive me crazy.

Here is what I do now when printing to an 8.5 x 11.0 inch page.

Open Document Properties (Shift+Ctrl+D)
Click on the Page Tab

If you want to print your image at 600 DPI set the Custom size to 5100x6600 pixels

If you want to print your image at 300 DPI (my default) set the Custom size to 2250x3300 pixels

If you want to print your image at 200 DPI set the Custom size to 1700x2200 pixels

Inkscape's default is 90 DPI which is 765x990 pixels

I hope this helps.

I am no geek, but this worked for me and a PC,

open your file, go to "Edit ->preferences", a menu window will open, go to "Bitmaps" and change "Default export resolution" to 300 dpi," Resolution for Create_Bitamap Copy" to 300 dpi, and Default import resolutio to whatever dpi you like.

Then close that window, and go to "file-> Export PNG image, choose Image size 300 dpi, and export. It worked like magic.