Distorted scanned image when rotated

  JerryH 07:14 27 May 06

I bought an HP Scanjet 4850 so I could make a computer record of my old 35mm slides. When I rotate a scanned slide by 90 deg (i.e. so it's a portrait), its dimensions as viewed are changed (short side is reduced from 71.5% of long side to 61%) and image is squashed to fit. If image is printed, it's OK, but I want a VIEWABLE record! This occurs whatever program I use to view the slide, so it has to be an HP problem. This seems an elementary matter, I'm getting nowhere with HP - anyone any ideas, please?

  €dstowe 07:24 27 May 06

Have you tried scanning all your slides as landscape and doing the rotating in the computer itself?

All graphics handling programs have facilities for turning through 90 degrees and most through any angle you wish. Evewn Windows Picture and Fax viewer will flip pictures through 90 deg. (or multiples) in either direction.

  Gongoozler 07:30 27 May 06

Hi JerryH. Surely if the printed image is OK then this is a display problem - unless I have misunderstood what you have said.
Try this. Using Irfanview (I like to use Irfanview because it doesn't try to be too clever) look at one of your pictures. Click on the i (Image information) button. Look at the image size and as before work out the ratio of the sides. Hi the keyboard R key to rotate the image. Now click on the i button and you should then get both the old and the new sizes. I find that these are simply interchanged to reflect the rotation.

  Gongoozler 06:59 29 May 06

I did as you suggested and certainly the image size in pixels is unchanged. But the viewed rotated image as viewed is nonetheless squashed as previously described, just as when I use Paint Shop Pro, Xara, etc. Thus problem seems to be the default setting my PC uses to display rotated images???


Hi Jerry. It's best to reply via the "Add a new response" box at the bottom of this page, that keeps the thread alive and lets other forum members join the discussion.

If the image size in pixels is unchanged, then I don't think it's the way the computer is handling the image, but the way the monitor is displaying them. What I think is happening is that the displayed vertical and horizontal pixel spacing is different.

  €dstowe 07:41 29 May 06

I've also had an email from JerryH:

"Thanks for answer, but problem occurs whatever program i use to rotate image (e.g. Paint Shop Pro, Xara), and this is so with images taken with different cameras (which logically is irrelevant!). So answer to problem would seem to be how to change the dimensions my PC chooses to display a rotated image????"

I agree with Gongoozler's reply - there is something wrong with the settings of your monitor.

  hssutton 08:52 29 May 06

If your scanned image is ok when viewed on your pC then rotating it will not affect the image shape/size.

However try converting your Jpeg? to Bitmap then rotate, you will be able to then re-convert to Jpeg after rotation.

  Gongoozler 13:35 30 May 06

If you have a vector drawing program on your computer, use it to draw a circle that fills the height of the screen. Knowing that the width of the circle is the same as the height means that you can judge the geometry of your monitor fairly accurately. Rotate the image and you will be able to see if the geometry changes.

If you don't have a vector drawing program, scan a paper image of an accurately drawn large circle and then do the same.

If the circle is correctly displayed before rotating it but becomes an ellipse, then the computer is doing something strange, but if the circle is elliptic in the same dimension (i.e. it is taller than it is wide or vice versa) even when rotated then it is the monitor that is doing the distorting.

  JerryH 20:11 31 May 06

Thks for continued interest, Gongoozler. I followed your 2nd suggestion and scanned in a perfect circle (as portrait), using my HP Scanjet 4850 as before. I then viewed via Paint Shop Pro. Circle was elliptical (taller than it was wide). When rotated 90 deg, it remained elliptical. I am sure I have never tampered with monitor settings, so I wonder how distortion arises.....???

  Gongoozler 21:44 31 May 06

Hi JerryH. The monitor geometry could have been out for as long as you've had it, and you just didn't notice it. Monitors tend to have resolution/refresh rates at which they work best, and other combinations can sometimes result in strange things happening.

  JerryH 16:33 03 Jun 06

Hi Gongoozler - thks again. Strange thing is, I get same problem with the Iiyama monitor I have on my other computer. How can exactly same problem occur on both, I ask myself? Also, I'm sure in every other respect monitor settings are fine, and that it's something to do with the standardised portrait photo-frame into which the rotated image is forced to fit when viewed. (Apart from that I have to admit I don't know how to adjust the resolution/refresh rates.....)

  Gongoozler 09:45 04 Jun 06

Hi JerryH. It's quite possible that the program you're using to view your images is distorting them to fit a frame. To see the geometry of your monitor, I think you really need a vector drawing program. I use CorelDraw which tells me accurately the actual size of an object in either pixels or millimetres so I can draw a circle and see on the screen that it really is circular. A quick Google search tells me that DrawPlus 4 and Inkscape are free vector drawing programs click here, I also found Microsoft Expression which looks good click here.

To check your resolution and refresh rates, right click on any unoccupied part of your desktop and select Properties - Settings. There you will see the resolution slider. Then click on the "Advanced" button and the "Monitor" tab, where you should see the refresh rate options. Note the settings before you try changing any. If you make any changes Windows will give you a few seconds to accept them before reverting back to the originals. This is to protect you in case you select a setting that your monitor can't display.

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