Gradients and transparencys not smooth

**con** · 22 May 2007, 09:10 AM

I got a lcd flat screen samsung 20" syncmaster 206BW, is it because of the screen gradients dont look smooth? Gradients just look like lines of diffrent color same thing with transparent colors. This is most noticible when I do big things like wallpaper and such, I dont notice this on smaller stuff like buttons and smaller logos or text.

I hope someone understands what I'm talking about, ask if you dont and I'll try to explain better.

**jamesmc** · 22 May 2007, 09:15 AM

A picture is worth a thousands words. Post an example maybe?

**con** · 22 May 2007, 09:22 AM

sorry about the big file size only thing I had here now...

**handrawn** · 22 May 2007, 12:45 PM

Looks OK on my Phillips 17" LCD.

Usually an LCD monitor will be supplied with a setup/optimization program which enables you to calibrate it.
If the brightness of the pixels across the screen is uneven this could cause banding problems.

Presumably you did not have this problem before you got the LCD screen?

**Soquili** · 22 May 2007, 01:05 PM

Banding can occur if you have less than 24bit True Color selected for your graphics card. Some drivers for graphics cards offer 32bit True Color, use the highest your driver provides.

If you did not install the driver for your new LCD monitor your graphics card may not recognise that is supports True Color and automatically limits you to 256 or even 16 color mode.

**fjgaude** · 22 May 2007, 02:14 PM

Originally Posted by con

sorry about the big file size only thing I had here now...

Looks perfect on my ViewSonic VP201s 20.1" monitor, 1600 x 1200 pixels. Make sure you have 24-bit color or higher.

frank

**jedfrechette** · 22 May 2007, 05:37 PM

Originally Posted by con

I got a lcd flat screen samsung 20" syncmaster 206BW, is it because of the screen gradients dont look smooth?

I don't think this has anything to do with your monitor. The horizontal banding in your example image, which is quite obvious to me, is present in the original image. Attached is a screen shot of your example with a profile plot of the grayscale values. The profile is along the vertical blue line and starts near the top of the image. It seems pretty clear that Xtreme is approximating the smooth gradient that you are after with a series of variable width lines.

I don't know if this is a bug in all Xtreme versions or just the Linux port.

**con** · 23 May 2007, 07:14 AM

thanks for your replies

I tried the xtreme demo on windows yesterday and i got the same "color lines" as in the linux version. I tried changing the settings on my monitor but the only change was either the screen got too dark to see anything or I could see the lines even clearer.

I've setup X to give me 96x96dpi and 1680x1050 resolution, colordepth is 32 bit (24 in xorg.conf). I can post my xorg.conf if you want.

Sorry for not replying earlier, had some problems with my dsl yesterday and still do. Called the phone company and they promised to come and fix it today.

Thanks again!

**con** · 24 May 2007, 08:34 PM

I'm quite sure its monitor that is at fault....I'm seeing the same banding effect other on graphics application I use, didnt notice this before....damn it. I wish I had a chance to try some real graphics programs before I bought this thing.

**ericgl** · 22 June 2007, 09:03 AM

Con, I know what your problem is as I have encountered the same annoying issue.
The technical term to this issue is called Banding.

I have a Dell 2007wfp 20" LCD monitor (revision A02) attached to a GeForce 7600GT PCIe card.

Sometimes when I view a certain image, gradients look awful with distinct color separations instead of looking smooth. This usually happens with Black-to-White gradients, BUT not in all my images.

I have discovered that when I view an image (in formats such as .PNG, .PSD) in ACDSee, the gradients have this problem. YET, when I view the same image in another application, such as Photoshop, CompuPic Pro or even the default Windows Picture & Fax Viewer that comes built-in with WindowsXP, the gradients look smooth as they should.

Even when I create an image in Photoshop that is 16bit/channel, the Banding issue is still apparent in ACDSee.

So, the problem doesn't lie with the monitor, but rather the application you're using to view the image.

P.S. On my 20" Dell LCD, the image you posted looks quite smooth, yet has a small amount of banding which I think is present in the original image, as pointed out by jedfrechette.

Hope this helps.
Eric G.