Spot Color Seps with Photoshop Channels

[starchild]

Hi everybody!

I was going through my routine search and discovery on the googles
and came across this 3 part separation tutorial series.
http://www.cedarboxcreative.com/color-seps-with-photoshop-channels-part-2

It's basically using the CMYK channels (after duplicating the image and then converting to CMYK) against each other to knock the colors out.

Thought it would be useful to someone or to contrast to the Jimmyo's spot color vid where he uses the color range command to select the colors.

[jsheridan]

I've found this guy to be the best so far...

http://www.youtube.com/eternyl#p/u

[starchild]

I've found this guy to be the best so far...

http://www.youtube.com/eternyl#p/u

Yeah I actually saved his tutorials to my drive using keepvid.com.
I like the use of the channel mixer window to select out the colors while in monochrome.
However the channel mixer only offers you RGB sliders to manipulate the hues and being that
the colors are being pulled in a gray scale anyway, I find that choosing the Black and White  adjustment command
offers more control over the hues because along with the RGB sliders you also get cyan, magenta and yellow for a higher level of control of the hues.

[Dottonedan]

I'm finding that we have even more ways to separate than I first thought.  Every time i yjink ive done it all, someone shows another way. I have done it using Eturnal's method. It is (one) way, but not yet the best. I think to know or learn the best methods, you might need to have the intentions of really improving your outcome. Often times, only those who want to make a living at separations are the ones who go this far. For most, these methods are all you need, especially starting out these options are ideal as they have no cost to them if you already have Photoshop.

[starchild]

I think to know or learn the best methods, you might need to have the intentions of really improving your outcome.

I really want to  learn or know the best methods and techniques. I'm after the "Why" use a particular procedure in the sep'n process to
achieve a required result. "When" do we use saturation and contrast commands? (levels, curves, vibrance etc.), when used in channels,
are destructive commands because we can't use adjustment layers in channels so we always move forward and can't pull back our edits. "Can we" use layers to build the sep using adjustment layers to retain balance and control of each screen/layer thus making the whole procedure non destructive? What are some of the better ways of selecting hues? I've learned on this board of using the calculations command to knock color out using channels against each other (It's the post with the sep'd phoenix) I only know calculations being used to mask more general areas, I thought the blend modes Add/Subtract was more of a luminescence operation and never considered the hues that can be selected by the various degrees of light blocking.

[Artelf2xs]

I really want to  learn or know the best methods and techniques. I'm after the "Why" use a particular procedure in the sep'n process to
achieve a required result.

Read my post from this am here

http://www.theshirtboard.com/index.php?topic=2113.msg23023#msg23023

[myseps]

"When" do we use saturation and contrast commands? (levels, curves, vibrance etc.), when used in channels,
are destructive commands because we can't use adjustment layers in channels so we always move forward and can't pull back our edits.
"Can we" use layers to build the sep using adjustment layers to retain balance and control of each screen/layer thus making the whole procedure non destructive? What are some of the better ways of selecting hues?

You can always command-z to go back 1 step, or use the history window to go back if you realize you want to change something.  As a last resort, It is wise to keep a layered version of the artwork, and you'll always be able to go back and grab that layer and re-do that portion of the separation.

I've learned on this board of using the calculations command to knock color out using channels against each other (It's the post with the sep'd phoenix) I only know calculations being used to mask more general areas, I thought the blend modes Add/Subtract was more of a luminescence operation and never considered the hues that can be selected by the various degrees of light blocking.

You can use any channel for knock outs.  Just load the channel to a selection, and delete.

[Dottonedan]

I really want to  learn or know the best methods and techniques. I'm after the "Why" use a particular procedure in the sep'n process to
achieve a required result. "When" do we use saturation and contrast commands? (levels, curves, vibrance etc.), when used in channels,
are destructive commands because we can't use adjustment layers in channels so we always move forward and can't pull back our edits. "Can we" use layers to build the sep using adjustment layers to retain balance and control of each screen/layer thus making the whole procedure non destructive?

No. The main reason to that is because most of those features you are referring to, only work in RGB and some in CMYK. Those editing features are for the appearance of the image and not for breaking down color for production. They are for the "art creating stage". The only ones you mentioned that I use in channels are the curves and levels. Mostly curves.  The others efect the art (as a whole) and if you want to adjust art in RGB or CMYK, do not use that for the separation process. Features that work in RGB or CMYK effect (ALL) channels. For example, if you have a single color red on a layer in either RGB or CMYK, it's got data or color content (on each one of those channels). That means, the R, the G and the B all have a % of color data that makes of that color you are looking at in the layers file. The same goes for CMYK. If you were to copy an image from a layer, (into a channel), is then paste in a grayscale equivalent or composite (into that ONE new channel). In channels, is where you then use levels or curves to adjust it for production (such as preparing for dot gain) or making mask's selections etc.

What are some of the better ways of selecting hues?

That really depends on what you mean by selecting hues.

I've learned on this board of using the calculations command to knock color out using channels against each other (It's the post with the sep'd phoenix) I only know calculations being used to mask more general areas,

. For me, I never use calculations for using them as a tool to knock out of or add to a color. I use them (on occasions) to pull out (to get a selection of a color area).

 

I thought the blend modes Add/Subtract was more of a luminescence operation and never considered the hues that can be selected by the various degrees of light blocking.

  Well,  you got me on that one. For the most part, modes again, are used in the creation stage of the art and not necessarily in the color separations or adjustments of each color. (not for me really), but they could be. I do know of one or two methods of obtaining separations uses modes, but not all modes will work the way you want. Going back to my statement about the RGB and CMYK being affected, take the MULTIPLY for example, If applied in CMYK, is actually adds more MORE BLACK to a color. That is how it makes it a darker color. In printing, adding more black to a color, can make it much more darker yet muddier. It's not a real clean way of adding or creating show color. (again, this is more so referring to the creation stage).

Sometimes, the best method for making color selections is working with a composite of the image on to a channel and then drawing selections using the pen tool and by eating away at color using the airbrush tool or adjusting curves and levels. There are other more complex methods but are often the sacred secrets people talk about.

Other way some artist use to get good separations is strictly by creating the art in channels to start with. Our old friend Jeri Cloe has a good tutorial on how this is done.  She's done it this way for years, (and is the same way I originally learned around 1991-92).  It's very effective if creating your own art for apparel.  The down side of doing it this way, is that you never do get to spread your wings so to speak and learn how to tackle the other side of separations. That, being the RGB and CMYK art side from those customer who send you flat art created by someone else.