May 26, 2006

Retaining spot colors without losing your marbles

My buddy Scott Citron sent me a file he was working on for a client. He had created a logo that had some pretty cool transparency effects in it. But the problem he was having was that he was trying to preserve the logo in spot colors, but because of the transparent effects in use, the colors were being converted to process.

The actual effect he was trying to simulate was a glass sphere, like a marble. There are tutorials all over the web which will teach you how to create these kinds of cool objects, but most of them use Photoshop to achieve the desired effects. That means it's more difficult to work with spot colors and more specifically, especially in the case of a logo, the ability to scale the art and maintain high quality is sacrificed.

The secret in getting this done is to use one of Illustrator's "hidden gems" -- the Opacity Mask. Besides the cool effects that Opacity Masks can create, Opacity Masks will also always preserve spot color information. That's just what we need for this technique, so take a look at the steps that I did to create a pretty cool looking glass marble. It's always fun to create cool stuff, but getting it to print correctly can make people lose their marbles (sorry, couldn't resist!). So it's especially gratifying when you learn to create something that not only looks totally cool, but that will print correctly as well.

Ready? Let's get started!

First, we'll start by creating a circle and fill it with a spot color.



Next, we'll modify the fill so that it uses a gradient. Here I set the gradient to go from 55% of the spot color to 100% of the spot color, and I adjusted the color stops and midpoint slider to get the effect I was looking for. I used a Radial Gradient and I also used the Gradient tool to offset the center of the gradient so that the center point was closer towards the bottom of the circle.



Now comes the important part. In other tutorials that you'll find, or what Scott actually did here, was he created an oval shape (as a highlight for the reflection) and filled it with a black to white gradient. He then set the oval to use the Screen blend mode, which gave hiim a nice highlight. Only problem is the Screen blend mode forced the spot color to separate as a process color. So instead, I took the same black to white gradient and drew a plain white-filled rectangle behind it. I also selected the oval and choose Effect > Stylize > Feather and gave it just the teeniest bit of a soft edge (because I liked it better that way). Then I chose the oval and the white rectangle behind it and opened my Transparency palette. From the flyout menu I chose Make Opacity Mask.



So what happened here? The gradient's luminosity values became a mask for the white rectangle and I achieved the desired effect of creating a light reflection on the underlying circle. Nice, right? And because I used an opacity mask, the spot color is preserved and will separate correctly. But we're not done yet...



I learned something valuable from another friend in the business -- Bert Monroy. He taught me that in real life, there's always something in a reflection. While the light itself makes the marble look nice, in real life, there's gotta be something that you can see in the reflection, which will make the object look more life like. So I took some random art and colored it 100% of the same spot color. In reality, you could also use a photograph here and colorize it with the spot color. I didn't do that here because I wanted to make the logo theoretically scalable to any size. So I used a vector shape.



Next, I created another circle and filled it with a black to white gradient. I then selected both the squiggly art and the gradient-filled circle and again created another opacity mask.



As a finishing touch, I set the squiggly art to the Mutliply blend mode and dropped its opacity to 15%. This created the look that something is reflecting off the shiny glass marble. As a finishing touch, I added a soft shadow to complete the look.



So in the end, we have a glass marble -- created entirely in Illustrator (I can't remember the name of that other program -- photo something -- photostop? -- eh, whatever) which can be scaled to print on an 80 foot billboard in Times Square, on the side of a blimp, and without ever having to convert to process colors.

Hmmm... all of this talk reminds of that great line from that cult classic Animal House. "Can I have ten thousand marbles please?" Time to go watch a DVD....

17 comments:

Scott Citron said...

Thanks Mordy for this great tip and for helping me out of a major jam!

Scott

John Kallios said...

I think I had a tear of joy well up in my eye.

Transparency and spot, working together…I'm all choked up.

:-)

Opacity masks, is there anything they can't do?

Mordy Golding said...

Scott -- glad I could help!

JK - Is it too sappy to say that while I was writing the post, I was thinking of you? :)

Mastering opacity masks is like having a secret weapon. Sad they don't get as much publicity as 3D and soft shadows....

Anne-Marie said...

tres cool, mordy!

I think the name of the product you were trying to remember toward the end there is actually called "photoslop" ...

Erin Sparling said...

I had to do something along these lines fairly recently, except I didn't think about adding that "imperfection" to the reflections.

When providing label artwork to our clients, its important to have background bottle renderings that look at close to the product as possible, without actually taking a photograph or providing linked artwork. For a recent request, they asked us to create clear actuators for bottles, and I had to use almost the identical technique.

Actuator transparency example

The bottles are composed of one spot color, and the caps are composed of two; one color for the plastic over-cap, one color for the actual plastic used to construct the actuator.

Using this technique, the "clearness" of the caps was completely flexible, where when the client said "ok, lets see these if the bottle were pink" I was able to easily redefine the colors and preserve the entire appearance of the artwork.

The caps themselves are just a solid or standard gradient fill, with a really, really involved opacity mask! Just thought I'd add in my two cents as to another real-world example of this technique.

Mordy Golding said...

Great use of opacity masks Erin! Thanks so much for sharing!

John Kallios said...

Nice Erin

I said it before and I will say it again.

Opacity masks, is there anything they can't do?

Sappy, no.

Creepy? ...

rodin1960 said...

Hi, very cool! When I saved the file as a Illustrator file a window popped up, "When spot colors are used with transparency, changing them to process colors outside of Illustrator can generate unexpected results." with a check box, "Don't Show Again". Will I have a problem with my Print House? Should I flatten the file?

MUST Gum Addict said...

No need to flatten the file. You should have no problems with printing.

PiT said...

perfect job, mordy

Anonymous said...

So then the Multiply blend mode and 15% transparency of the internal reflected object doesn't convert the spot to processes the way the Screen blend mode does?

Is it merely specific blend modes that result in spots converting?

Nice tip Mordy :) Thanks.

Mordy Golding said...

Correct. Mutliply preserves spot colors. I can't remember all of the blend modes that force a process color conversion, but they certainly include screen and difference for sure...

Anonymous said...

Hi, just wondering if you could help with screen blend mode. It is working OK in Photoshop but in Illustrator I just get white color over the top of whatever color when I use black to white gradient, just can't get any 3D effect out of it. Also some other blend modes don't make any changes. Any Idea ?
thanks

xpace

Anonymous said...

To "xpace"

When using "black" in the screen blend mode (such as in your black to white gradient), use a "rich black" to get the desired effect.

By "rich black" I mean that the CMY components also have a value. For a full 100% "rich black" set all the CMYK values to 100%.

Anonymous said...

any way to do this with a square or rectangle shape...?

Sching Ng said...

Thanks for the great tip ...have been trying to figure this out for a while. One problem I'm having is shifting the centre of the gradient circle to be closer to the bottom. No matter what percentages I use it's still centred ?

thanks
Sching

Sching Ng said...

So grateful for this ...
However I'm not able to shift the centre of the radial gradient off to the bottom, no matter what percentage i try. What did i do wrong ?

thanks
Sching