Topic awaiting preservation: Exploding Data, Bad Lum, and Things (Page 1 of 1)

Long day, so I'm going to relax by rambling for a bit.
I find it soothing.

High Pass Mask
Sometimes I compliment this with Find Edges.
Depends on how big of a High Pass value I use.
Do High Pass mask, Find Edges, then Multiply them.
No biggie.

Crappy Lum
I enjoy tearing photos apart. Allows me to see the little things that add up to big badness.
Fix the little things a little at a time, and eventually it's all good.

However, I don't like it when the Lum is crappy.
But that's how it goes and it has to dealt with.

1. One kind of crappy lum comes from compression. The 'lower levels' of compression just plain suck. The only acceptable way of this that I have found of fixing this is Bicubic.
Copy
Free Transform down to 35%-50%.
Free Transform back to original size.
Works much better than I expected.
I hear that PS CS has more interpolation options, so feel free to experiment.
(A trick I learned from my days with my Amiga. Why, I'm almost surprised that it's still useful.)

2. High Pass giveth; High Pass taketh away.
For broader noise, around 3-10px, High Pass works fairly well.
You know, the opposite of using High Pass to sharpen.
Copy
High Pass
Invert
Set to Linear Light, Hard Light, or whatever.
Tweak from there.
Takes a decent chunk of noise away, but can also blow the details.
Kind of a trade-off and defeats the purpose (noise vs. detail), but I like.
Also an interesting way of softening a photo.

Exploding Data
Or, more accurately, Expand and Contract

This is a trick that I seriously adore. Started using this in my big D-Map tricks. Did you notice it?
Let's say that I want a gradient that goes Grey<>White.
Instead of doing just that, I'll go Black<>White, then Level/Curve to the range.
What this does is allow more room for tweaking.
After tweakage, the range is made proper.
Would you rather have the entire Curves dialog available or just half?
Yeah, baby. Yeah.

I've been using that same idea for things chromatic.

Grab some random photo.
Image > Mode > Lab
Levels
In Levels, go to channel a and hit Auto.
Write down the numbers.
Leave channel a in Auto.
Go to channel b and hit Auto.
Write down the numbers.
Go ahead and leave Levels with a and b Auto Levelified.

In the channels palette, both a and b should be all jaggified to the max.
Go ahead and use your favorite method to smooth it out.
For example, High Pass Mask Blurring.
Or maybe even get crazy with Smudge.
Or whatever.

When you are done smoothifying a and b, go back to the layers palette.
Add a Levels Ad-Layer.
Go to channel a and enter the numbers in the bottom two fields.
Go to channel b and enter the numbers in the bottom two fields.

If the smoothing went well, you should be looking at pretty much the same photo that you started with.

Ah, but there is a big difference.
That difference being the extra data that you tossed in when you smoothed a and b.
That extra data can seriously come in handy.

For example, fixing a variety of chromatic abberations should be *tons* easier.
Or, if you get a bit extreme with certain adjustment, you shouldn't get terribly nasty stair-stepping.

I did spend quite a bit of time with some rather nasty scans.
Using what I said at the beginning, I was able to get an acceptable Lum.
Then, by exploding the chroma, I was able to fix the funky colours.
A touch of trial-n-error aside, it was no sweat at all.

I've also used some of these tricks for photo restoration.

And then there was that one time...

Ah, I'll leave you to it.

I think I just got some exploding head...

Exactly what just happened?

Lum? I suddenly need a secret dictionary to read the forum! This is what I get for leaving for so long.

Hey, Sloloem.
Is this just a cameo are will you be hanging out for awhile?
I know I miss your presence.

Lum = Luminosity
As in the L channel in Lab mode.
Or the Luminosity blending mode.
Sometimes known as Lightness or even Brightness.
A few crazy people even use Value.
There are technical differences, but I don't have the strength to untangle that particular mess.

This will explain some of the High Pass stuff that I mentioned:
http://www.ozoneasylum.com/24112

Might help bring you back up to speed if ya got the yarble for it.

slo's been around a while now, he was a Christmas present I guess

wj, can you mail me - jason at disk919 dot com? I mailed you about a week ago via the board here but not sure you got it

back to your regularly scheduled...

Heh. It was sitting in my trash.
I'm totally not used to getting e-mail.
The best way to contact me via e-mail is to drop me a note in forums to give me a heads-up.
Otherwise my eyeballs probably won't catch it.

I'll get to it tomorrow.
Serious brain fry is starting to set in.
Nightie night.

OOoooohhhhh... luminosity! i thought you mean lum, as in the contraction of Lomin Ale, the Star Wars equivilant of Guiness


Justice 4 Pat Richard

wow.........i have no idea what i just read. It seems that you have a lot of these "in-depth" posts about color and stuff. Are you doing some research or something? Just a hobby?

Later,

C:\

Wow !!!! Now thast was an interesting read (believe it or not)

I have been doing a lot of working with photography, restoration to be exact and some of your methods described will definatley come in handy.

I also have a series of photographs that have suffered from a lot of noise due to the bad lighting i was forced to shoot them in, and i am sure that some of the tricks you mentioned for lum will work a treat, as the methods i have used in the past, whilst acceptable, can be improved upon.

I found your comments about compression to be interesting also, the effects of using transform in that way is something i will have to experiment with.

Warjournal, Have you ever been to www.retouchpro.com ? They have some interesting topics for discussion and some interesting challenges, for instance, there was a letter that vame back in the post and it had black marker of the address and they wanted to see how many people could actually read the address. I mean it was black to the naked eye, but using a variety of techniques, members were able to get a full address of it, was actually an interesting topic and unvieled a host of helpful techniques.

Right now, mostly hobby. Prolly be another year or so before I start free-lancing thing kind of stuff again.

Not really research, but exploring. Tearing things apart, looking at the pieces (tools, techniques, basic ideas), and fitting them together in different ways. I've always been insanely curious. Why, I can be dangerous with a screwdriver if left alone for too long.

(At my old job I was a service tech. I was tearing things apart all day long and it was great. When working on high-voltage things, make sure your pager/beeper is not set to vibrate. And things...)

I've been to Retouch Pro a few times.
Spent some time lurking yesterday.
Picked up 2 Nuggets o' Joy and noticed some mistakes.
Undecided if I'll join.
Although, VP has been known to haunt Retourch Pro.