Add noise/dithering to gradient when exporting?

[feklee]

When exporting to 24 bit (!) JPEG or PNG, I would like to add some noise/dithering to gradients - is this possible?

Here is why: When gradients are too clean, stripes / banding may be visible when printing.

[gwpriester]

What product are you using? Your Profile does not say.

[mwenz]

When exporting to 24 bit (!) JPEG or PNG, I would like to add some noise/dithering to gradients - is this possible?

Here is why: When gradients are too clean, stripes / banding may be visible when printing.

I don't know about some of the other Xara products, here I am using Designer Pro.

Select your object, Live Effects (ctrl+F5, the plug icon), Distortion Filter, Add noise.

Take care, Mike

[feklee]

I just applied the solution recommended in another thread, and it seems to do the trick: Apply the Diffuse live effect, and clip the object with the desired shape.

It would be nice, though, if there was an easier way in Xara Designer.

[angelize]

Mike's solution above is better than diffuse as you can easily set the strength and density of the noise and no clipping is required.

[feklee]

Frances, I checked the noise effect as well, and in fact I use it somewhere in that illustration. However, for the gradient I believe that diffusion is the higher quality option, although a bit cumbersome.

[gwpriester]

How are you exporting your image? And at what color depth?

[feklee]

How are you exporting your image? And at what color depth?

Hi-res 24bit JPEG with 100% quality.

Currently the target is a photo printer which works with sRGB color space (prints are developed). In the illustration there is a gradient taking up a major part of the page, and in tests with dye-sublimation printers (CMYO), I have seen ugly banding. Applying the diffuse filter makes the banding disappear.

[gwpriester]

I would never use JPEG for anything other than web work. PNG or TIFF are better, and TIFF with no compression is better still.

As a test I just printed three sets of two 8" tall x 1" wide panels with gradient fills. One of the fills was white to black. The other was similar but each of the two colors had some saturation added, 10% 210 Hue for the white, and 20% saturation for a dark red/black.

I exported each set at 300dpi, JPEG 0% compression, PNG 24-bit, and TIFF 24 bit and printed a test sheet on my HP deskjet printer using the presentation printing setting and the Best quality. I printed on high quality matt finish cover stock.

I get no banding on any of the panels.

So alot must have to do with the printer driver.

[feklee]

I would never use JPEG for anything other than web work. PNG or TIFF are better, and perhaps TIFF with no compression.

I am not sure if the target printer understands anything other than JPEG. After all JPEG is the image format in photography, and the printer is targeted at outputting photos. Of course, there is TIFF, but it has countless of dialects and is therefore not always easy to handle.

300dpi

I also used 300dpi on a greater than A4 sized page, scaled down to 10x15cm when printing.

I get no banding on any of the panels.

Depends on the printer. Be sure to look closely and perhaps compare with diffusion effect applied. With the dye-sublimation printer that I tried, however, there is no need to look closely: The banding effect is very strong. Also note, that I did some test prints directly from Xara.

The gradient, by the way, is blue (#3f40d0) to white, from bottom to top.