today i made the "Analysis" picture for my blog

http://gimp-science-labs.blogspot.de/20 ... lysis.html

it was done im Gimp with a PPI of 300

then i did the text overlays in Inkscape, because i find it easier to work with text in IS
so i imported the picture into IS and worked on the text
then delete the picture, so i was left with the text only and when i tried to export
it said 90dpi....

is that the default for Inkscape ?


then i tried to change the dpi to 300, because it seemed reasonable to have both pictures at the same dpi/ppi
but the higher i went, the bigger the text-pic became.....

which leads me to the question:
how do i maintain the size of my picture in IS, but increase the dpi ?

The key word here is "size". When you say you want to maintain the "size" of your image in Inkscape, what "size" are you referring to? Because if you mean the number of pixels, then trying to increase the dpi/ppi means having more pixels.

Don't think in dpi, use the actual image size.
Say your Gimp image is 640x360 pix then make the inkscape page size 640x360 pix
Then export the page and it will be 640x360 pix.
When imported into Gimp as a layer it will be the correct size.

Now you can think about assigning a dpi value.

*scratches head*

thanks for the answers guys, im still confused, so bear with me if im asking more noob questions

1600x900px


this i understand, pretty logical

right, but i just copy and pasted my original Gimp pic into Inkscape...
obviously im expecting it to be of the same size and dpi as in Gimp....

errrr, but then the pixelsize will grow again with the ppi.....

right, so i tried it all again - its getting slightly clearer
copy and pasted the 1600x900px, 300dpi picture from Gimp into Inkscape

when i open export in IS it says 2329x1310px, 131ppi under Bitmap Size, but the page size is the same as in Gimp
i didnt notice that at first
why is it not the same pixel size and dpi as in Gimp ????

can i change the Bitmap Size all the way i want ?

Ok I am one post behind

I hope you do not just copy and paste. Import your gimp image then in Inkscape document properties set resize page to drawing or selection. That will remove any excess and stop you screwing up the size.

Now do your editing, preferably on a new layer then you get rid of your background & export as a png with the correct size for your gimp image.

Screenshots of this, a bit of a chinese scroll so not posted in line. http://i.imgur.com/Lxyhj12.jpg should be self-explanatory

Why is it just the bitmap size that matters.



Top pair.
Two images both 300x300 pix but one has a dpi of 100 set and the other has a dpi of 300 set
In default Gimp with View -> dot-for-dot set ie one image pixel = one screen pixel they are (of course) the same size.

Bottom pair
Same 2 images but now View -> dot-for-dot is turned off for both, this is how they would look in a web browser or if you printed at those settings. Left is 3 times larger than right.
but both are still 300x300 pix it is the image size that matters.

*sigh*

i dont get it....at all.....

will have to do my homework first it seems, as im confusing a lot of things

will come back later to this thread

AFAIK Inkscape treats all bitmaps as 90DPI.

So your 1600x900px, 300dpi picture from Gimp becomes (for some reason) 2329x1310px, 131ppi which really IS 1600x900px@90dpi (2329*90/131=1600 and 1310*90/131=900)

-Rob A>

thanks RobA for the added info !



okay, i googled all day and evening to wrap my head around dpi and bitmapsize and all that stuff because when rich2005 said a 300dpi pic is smaller than a 72dpi, my head almost exploded

man, this stuff is more complicated than quantum mechanics

so i found a good explanation in german here:
http://www.gimpforum.de/showthread.php? ... #post52891

and one thing that maybe confused me as well, is the use of inches
i know what an inch is, but here in germany (and most of europe) we have the metric system, so converting that into millimeters helped me grasp the ideas better, i think

72dpi = 2,8dpmm
300dpi = 11,8dpmm



right, so if i understand you correctly you are saying :
just make the Inkscape text layer the correct pixelsize, dont care about dpi when exporting and import it as a layer into Gimp

which leads me to my initial question:

if my Gimp picture is 300dpi, but the imported textlayer from Inkscape is only 90dpi at 1600x900px, that doesnt matter ?
or do i still miss something ?