Dan Margulis Applied Color Theory
Fireworks
Date: Sat, 25 Jun 2005 14:57:39 -0500
From: Jim Bean
Subject: fireworks
just delivered a few cmyk firework images as a last
minute favor for regional magazine cover.. considering the extreme amount
of black ink that was going to applied.. I was wondering what the 'best
practices' may be for these images.. color shifts are not a concern, .
however, the 'starbursts' not being closed up by excessive ink was a
consideration.. regards, jim bean
___________________________________________________________________________
Date: Sun, 26 Jun 2005 13:20:59 EDT
From: Dan Margulis
Subject: Re: fireworks
Jim Bean writes,
just delivered a few cmyk firework images as a last
minute favor for
regional magazine cover.. considering the extreme
amount of black ink that was going
to applied.. I was wondering what the 'best practices'
may be for these
images.. color shifts are not a concern, . however, the
'starbursts' not being
closed up by excessive ink was a consideration.
Fireworks shots are tricky things. Obviously you don't
have a prayer of getting anything as intense as a live viewer would see.
Therefore you do want to make the night sky as dark as possible (95K I
would think) and the problem of that black of a color so close to the
exploding fireworks is a real one.
The sharpening of fireworks shots is quite critical and
often involves uses of several Radii, plus Lighten and Darken mode. To get
the sky to recede from the bursts without actually making the bursts
themselves bigger, here are a couple of ideas that work well, one in LAB,
one in RGB.
LAB Move:
On a duplicate layer, sharpen the B (yes, the B) with a
very high radius. This is likely to massacre the bursts themselves, and if
so, apply the original B to the sharpened B in Darken mode. This
combination will give a big blue halo around the bursts, making them seem
more yellow and forcing the sky itself slightly lighter to accommodate the
blue color.
RGB Move:
1) Make and save a luminosity mask by
Command-Option-tilde, then Save Selection into a new channel.
2) In this new channel, not the RGB image, bring down
the shadow end of the curve so that the sky is dark but not too dark, maybe
75% of what it used to be.
3) Sharpen this lightened copy with a Radius of about
50 and an Amount of 500%.
4) Return to the composite color, and make a duplicate
layer.
5) To the duplicate layer, apply the sharpened new
channel, INVERT checked, mode OVERLAY.
6) Change the mode of the duplicate layer to LIGHTEN.
Like the first move, this will create a diffuse halo
around the bursts. Obviously you set opacities to taste, the way I
described it is going to be very intense.
Dan Margulis