Gradients

[Stacey K]

I have some experience with gradients but I would like to know the proper way to do this. I have artwork from a graphic designer (maybe this is my first problem) and it's worked well for the past uses in small capacities. I've also created a nice screen for screen printing which some of you helped me with - turned out really nice so thank you!

He ordered a larger print and when I increase the art to 4' x 4' the gradient is banding - it seems amplified on the print vs what I saw on my screen. What is the proper way to create a nice gradient so it doesn't band? I've read some people apply a blur to it.

I saved the artwork as a jpeg sized correctly at approx 4'x4' using LXI and uploaded to Signs365.

 

[Solventinkjet]

Is the file in vector format originally or is it a bitmap? If it's vector, scaling before saving as JPG should work although I'd suggest saving as a TIFF instead. If it's bitmap to begin with and then you enlarge, it's going to look rough because no new data is being introduced. Ideally it would all be vector and you save it as a PDF or EPS and let the RIP do it's thing but I know Signs365 doesn't except those file types.

 

[Notarealsignguy]

If it's vector, I think you can increase the number of steps in the gradient. They also seem to be smoother if you can go from end to end without anything in between. If that makes any sense? If you open it up, it will probably have a bunch of nodes (or whatever they're called) across the whole thing.

 

[Adam Vreeke]

Honestly that looks like it was almost created in photoshop. Not only is the gradient banding, but you are getting some shifty stuff around the edges of the triangle and the text. I would send him a screenshot of what you are seeing and tell him you need it in vector to properly size up.

 

[weyandsign]

You can upload EPS vector files to Signs365.

 

[Bobby H]

Gradients in vector-based objects can be hit or miss with having banding issues in the print output. Some of it depends on the application used to create the graphics. The printer and/or RIP can be a factor too.

Generally I get the best results printing vector gradients when using Adobe Illustrator generated PDF files in a RIP with Adobe-licensed PDF tech. The gradient steps appear almost infinite, very smooth. One still must use caution with things like grayscale gradients. There is a higher risk of banding issues when using a single ink color like Black for those kinds of gradients. CMYK-based grayscale gradients will print smoother, plus blacks will be deeper. For newer Illustrator-dependent gradient effects, such as gradients on line strokes or free-form gradients, it's critical for the RIP to be Adobe-certified and updated to support those features.

CorelDRAW defaults to 256 steps in its fountain fills, but can be upped to 999 steps. EPS and PDF files exported from Corel may print with better quality levels (similar to that of Illustrator artwork), depending on what the RIP does with the artwork.

I don't know what kind of strengths or limitations are built into gradient fills in Vinyl Express LXi artwork. I don't use that application.

I dislike exporting vector artwork in lossy compressed pixel image formats like JPEG, especially for any print purposes. All sorts of nasty things happen to the artwork in the compression stage. A gradient fill can be riddled with banding issues due to chroma subsampling methods used to discard data and lower file sizes. "Mosquito noise," macro-blocking and other blotchy issues can get baked into the artwork depending on the severity level of compression chosen. A lossless LZW-compressed TIF or even a PNG24 image would be far less harmful than JPEG.

 

[rjssigns]

For flawless gradients I use the Blend tool in Illustrator.

Learned that trick from my college illustration instructor.

 

[bob]

A gradient is bands of different colors. When you print a gradient it shows up as bands of different colors because that's what it is. Turn the gradient into a bitmap and add ~10% noise. This is the sovereign remedy for printing gradients showing no banding. What it does is scramble the edges of each band.