Choppy, lined gradients

[KateJ123]

i notice that when i'm making artwork and i'm using the gradient tool (in cs3 professional, currently, but i've noticed it in other versions, too) that the gradient isn't... fluid or completely blended, if that makes sense. it looks choppy. for instance, i can see the rings in this gradient i made:

http://jenniferdesigns-online.com/rings.jpg

is there any way to stop this from happening and for the gradient to be completely smooth without noticeable lines?  i found a couple of threads in the history but none of them seemed to actually answer the question. i'm saving in jpg format, i've got the dither checked, ...i'm not sure what else i can do. Any help for the noob is appreciated!

[KateJ123]

NOTE: Please note you should open the image in a new tab/window and see it at maximum size to be able to see the problem.

[getho]

although you have 8 bits of color info per channel which gives you 16million colours if I remember rightly, you are creating a gradient over 2 quite similar shades, so you'll be able to start seeing the steps from one colour to the next (Imagine you were making a gradient on agrayscale image with 256 greys - you'd be able to see where one grey changed to the next - this is the same except your going from color 15,999,748-16,000,000!!)

I've got an identity which uses VERY similar colours - complete with circular gradient, I ended up making the colour difference bigger (darker grey lighter grey).  I removed any adjustment layers that were on top of the gradient (so the colours are determined only by the foreground and background colours).

Use the biggest colour space you can (eg adobe RGB, or if CMYK something like the FOGRA space).  Add LOTS of noise.  If its something you are printing yourself you can try moving to 16bit - may make a small difference in windows (bigger difference on macs with printers with 16bit drivers, or on windows with certain pro canon printers).

[Semaphoric]

Add some noise.

[Mylenium]

As gheto said, you are using too little differentiation between the individual levels. The following happens:

Your colors are 19:36:44 (bottom right) and 69:82:90 (gradient center). With a little math we arrive at the following:

Red:    69-19=50
Green:  82-36=46
Blue:   90-44=46

Therefore the maximum available number of discrete color steps in 8bit is

50x46x46=105800

These colors spread across an area of about 928x555 pixels, ergo

928x555=515040
105800/515040=0.208...-

meaning that within that field not each pixel can have a unique color (te result would have to be 1 or higher). The ratio of available colors to required ones is about 1:5. Therefore the only thing the program can do, is to use the same color for multiple pixels, which in your case happens to occur along the radius of the gradient circle. Now, as suggested, adding noise may make it vissually less noticable because it introduces a random element, but even this form of random dithering does not change the fact that you still are running low on colors.

The logical conclusions therefore must be:

- use the maximum color range you can use, i.e. b/w gradients, wherever possible

- color them using gradient tints or by putting layers above them and using blending modes and opacity adjustments

- work in 16bit or 32bit to get more color levels

- save to 16bit or 32 bit formats

- only reduce the gamut/ color range for final output with respect to color profiles and other requirements, e.g. in web graphics

- if you work in 8bpc, make sure to not exceeed certain dimensions that cannot cover the limited fidelity

Mylenium

[Zeno Bokor]

you guys are killing me with all this math for such a small problem.

Make sure that you have Dither selected in the Options Bar before drawing the gradient