- [Instructor] In this movie,
we'll take a look at the effect of color space,
that is rgb versus cmyk,
on blend modes.
And to make a long story short,
blend modes are designed specifically to work in rgb.
They started in Photoshop after all.
And so, they often don't work nearly as well in cmyk,
especially the brightening modes such as screen.
And that's ultimately the result
of having that additional black ink.
Alright, so, I've got two versions of this file open.
I'm going to go ahead and switch over
to the comparative file here.
Currently they're both in rgb,
as you can see up here in the title tab.
I'm going to switch this guy to cmyk
by going to the file menu.
Choosing document color mode.
And choosing cmyk color.
And you'll immediately notice
the saturation levels disappearing
in that violent gradient.
And that's just because cmyk cannot express
a lot of these colors.
Now notice that this is a one-way operation.
If I return to the file menu,
choose document color mode,
and choose rgb color again.
Ill bring back some of the colors in my placed image
because after all,
it's linked to an rgb file on disk.
But I'm not going to bring back the gradient.
I would have to reassign those colors manually
because they have been converted to cmyk values.
But I'm going to press control z,
or command z on a Mac,
so that the right hand image is in the cmyk space,
as we can see up here in the title tab.
And incidentally, I've hidden my right side panels
by pressing shift tab
just so that we have some more room on screen.
Now I'm going to go ahead and select the image
on the left hand side here.
And I'm going to hide those selection edges
by pressing control h,
or command h on a Mac,
and if you'll permit me,
just for the sake of expediency
so that we don't have to keep bringing
up the transparency panel
I will rely on my dq shortcuts.
So I'll press shift one to switch the image
to switch the image to the multiply blend mode.
And I want you to notice here
this stroke
because the blend mode is assigned to the entire object
it's assigned to the stroke as well.
And so, if I were to switch it to screen,
by pressing shift two,
that black stroke is going to drop away
because black is always transparent
when combined with the screen mode.
So I just want you to bear that in mind.
Switch back to multiply, like so,
and I'll go ahead and recenter my zoom.
Here we are looking at the image
set to the multiply blend mode
in the rgb space.
Now I'll click on the cmyk image.
Once again press control h,
or command h on a Mac,
and I'll press shift one.
And you can see that we get,
if nothing else,
a dingier effect
that's a lot heavier where the black is concerned.
And that's because we're burning in the shadows
where the black ink is concerned.
And so, the shadow under the lip is darker.
And we have higher contrast effects throughout the face.
And so that's just something to bear in mind.
It doesn't look too bad.
It looks okay.
And one of the reasons is
because multiply and cmyk go hand and hand.
When you're laying inks on top of each other
you're effectively multiplying those inks together.
That's not the case where screen is concerned however.
So I'll just go ahead and switch over to the first window
and I'll press shift two this time around
in order to achieve that kind of floating head effect.
Very nice smooth highlights.
Now I'll switch over to the cmyk image
and press shift two.
You can see that the effect is totally different.
And that's because of that black ink.
And so to see what that looks like
I'll go up to the window menu
and I'll choose separations preview
to bring up the separations preview panel right here.
I'll turn on the over print preview check box.
And then I'll go ahead and turn off the colorful inks,
that is cyan, magenta, and yellow.
And you can see this is what we have in the black channel.
Nothing.
So we've just basically wiped out that black channel.
And as a result, we have nothing to go on
but cyan, magenta, and yellow,
which is why we end up with this very washed out effect.
So screen in particular
is just not going to work out very well in cmyk
unless you take the time to remove black as an ingredient
from whatever object it is,
gradient or otherwise,
that you're assigning the blend mode to.
So I'll just go ahead and switch back to cmyk here.
Let's take a look at a couple of other guys.
For example, overlay
in rgb.
And then over here in cmyk
we have overlay.
Overlay is definitely getting sacrificed
where cmyk is concerned.
Whereas, if I switch back to rgb
and press shift five for hard light,
and then switch to cmyk
and press shift five,
the effect holds up a whole lot better.
We do have some very high contrast transitions
but it's not a bad looking effect.
I'm going to skip ahead here,
this time around,
by selecting the image in rgb once again.
And this time I'll just press shift eight,
in order to switch to luminosity.
Which looks absolutely gorgeous here in rgb.
I'll go ahead and apply it to cmyk,
and it looks great here.
Now of course, we're not going to have
those super saturated violets
that we have in rgb
because cmyk does not support them.
But otherwise the effect is looking great.
And that's because we are able
to take advantage of all four of those inks.
Now let's take a look at the effect that really falls apart,
and that's difference.
Which I'll apply by pressing shift nine.
It ends up looking like a very colorful floating head
here in rgb.
If I apply it in cmyk,
it ends up looking like nothing of the kind.
And here's the reason.
I'll go ahead and turn off black for a moment.
And you can see
that we have a similar effect going to rgb
if we only rely on cyan, magenta, and yellow.
But what's happening
is that the black channel is completely inverting,
as we're seeing here,
and that provides us with a very different effect.
There's nothing analogous to the black channel
when you're working with an rgb image.
So, you may wonder at this point,
so does that mean if I want to work with blend modes,
I need to work in a cmyk color space.
Well, obviously you're going to get better results.
There's no doubt there.
And it is a good way to work.
Increasingly I'm finding myself,
regardless of what the final destination for a job is,
I'll start it in rgb
and then convert it to cmyk.
That does mean I'm going
to compromise my colors in the conversion.
But sometimes that's worth it.
Especially if you want to take advantage of blend modes.
Another option that's available to you
is to start in cmyk,
and then switch back to rgb.
That's going to sound like a little bit of heresy
but here's what it looks like.
I'll go ahead and turn all the inks back on.
I'm still working inside the cmyk image.
You can see that it's highlighted
over here in the right hand side of the screen.
And I'll go over to the file menu.
Choose document color mode.
And choose rgb color.
Now that doesn't restore any of the saturation
to the cmyk safe colors in the gradient.
But it gives us a much more satisfying effect
where the difference mode
in particular right now is concerned.
And so notice also,
we get a much better effect
where screen is concerned.
We once again gain access to our familiar floating head
even if it's a little washed out
compared to the rgb version.
But they are very akin to each other.
And so, my recommended work flow,
if you're ultimately bound for commercial reproduction,
is to assign all of your colors cmyk safe values.
And then, if you want to take advantage of blend modes
work in the rgb color space.
And as outlandish as that sounds
what you can then do is place the file into,
for example,
in design and convert it to cmyk at that point
after the effects have already been assigned.
But again, if you try to convert this file from rgb,
even though these are cmyk safe colors,
if you try to convert the file
to the cmyk color mode,
then that screen effect in particular
may very well end up going awry.