Gamma manipulation and the degree of contrast on cameo coins.

Russ · July 24, 2003 12:33PM

Tom's thread about the 1964 NGC PR68CAM Jefferson is the genesis for this thread. The fact is that's it's very easy to make a coin look like it has more contrast and is frostier than it really is. This can be done with lighting and angle, but also through software manipulation. One of the simplest methods is gamma adjustment.

Here's a coin image that I pulled down from eBay a while back:

I wanted to get an idea of how it might appear in reality, so I inverted it:

After reading Tom's thread, I cranked up the gamma:

Sure makes it look like a monster deep cameo.

Russ, NCNE

airplanenut · July 24, 2003 12:37PM

Great thread, Russ... so, do you do that to all of your monster DCAMs? You seem to know so well...

RGL · July 24, 2003 12:38PM

Gee, Russ ... that's how you created your icon coin, eh?

mojorizn · July 24, 2003 12:43PM

That's scary Russ. Thanks for the education. I run a lot of comic book auctions and frequently play with the color and contrast to better show the actual appearance. Didn't know that particular trick existed.

Mojo

Russ · July 24, 2003 12:44PM

RGL,

Nah, the mint adjusted the gamma on that one.

Russ, NCNE

DHeath · July 24, 2003 12:46PM

Can images be manipulated?

RGL · July 24, 2003 12:49PM

Hmmm, I'm familiar with early Jeff proofs with so-called woodgrain toning (don't care for 'em), but may be a first on a modern ...

airplanenut · July 24, 2003 12:49PM

<< Can images be manipulated?

>>

DanC · July 24, 2003 12:50PM

True. However - there is a considerable degree of "noise" in the fields which would be something of a telltale sign of overly agressive gamma adjustment.

To properly "doctor" the image - you'd need to brush the fields to remove the noise. I could do an example - but I need to prepare for tomorrows interview.

Dog97 · July 24, 2003 1:04PM

Russ when I snag pict #3 & invert it it looks like the fields have been touched up. Did you work on the fields or is that just some noise?

Russ · July 24, 2003 1:09PM

Dog,

Nope, didn't do anything other than gamma. Picture was worked in the original. Cranking up the gamma exposes it.

Russ, NCNE

KlectorKid · July 24, 2003 1:11PM

Now this coin would be solid for a 65. No shaving nicks on this lady.

I think the odd colors when you invert it are from the increased gamma.

DanC · July 24, 2003 1:17PM

crank the gamma on this...

Now it looks alot like a certain large coin dealer's shot from any of their auctions. (without naming names)

DanC · July 24, 2003 1:22PM

<< I think the odd colors when you invert it are from the increased gamma. >>

Huh? What odd color?

airplanenut · July 24, 2003 1:25PM

<< True. However - there is a considerable degree of "noise" in the fields which would be something of a telltale sign of overly agressive gamma adjustment.

To properly "doctor" the image - you'd need to brush the fields to remove the noise. I could do an example - but I need to prepare for tomorrows interview.

>>

Ahhh... but suppose I wanted to do this... I have a 2274x1704 image (4 MP) and I do the gamma trick... then I scale it down to even 800x600... still a large picture, but only 12.4% the size... the noise will be almost completely, if not completely gone.

Russ' noise is because the image was small to begin with, so there was no recourse to lowering the quality on that step.

Jeremy

shylock · July 24, 2003 1:25PM

Don - I like your desktop veneer Washington!

Wasn't it Einstein who said about photo editing tools "For every action there is an equal and opposite reaction"?

DCAMFranklin · July 24, 2003 1:26PM

<< Now it looks alot like a certain large coin dealer's shot from any of their auctions. (without naming names) >>

You don't have to.

Russ · July 24, 2003 1:27PM

Damn, Dan, you're scary!

Russ, NCNE

DanC · July 24, 2003 1:28PM

Might want to look again Jeremy. Size is immaterial. My point is only that if you choose to "doctor" an image - it can be made utterly undectable.

I might add... just because I can - doesn't mean I do.

Edit:

Russ - "Scary?" Hardly. Child's play.
It comes from about 12 years of doing graphic work. Maybe some day I should try some of that "expensive"
software.

There are about a million ways to cheat aren't there? I suspect the buyer of that doctored image example coin
would have a legitimate beef.

KlectorKid · July 24, 2003 1:34PM

DanC I was explaining to dog that when you crank up the gamma the picture starts getting messed up. I didnt do it on my pic doctoring work of art and you have to mess with more because my pic wasnt messed with as much.

DanC · July 24, 2003 1:36PM

I wasn't jumping on you Klector... just showing how quickly it can be corrected.

The thread - and every observation in it is useful - including your comments and picture. No offense intended.

OK - enough fun for me - gotta scoot.

BTW... What's this "Kitty Loaf" thing?

LucyBop · July 24, 2003 1:43PM

picking on a kiddy-o eh, I'll handle you!

KlectorKid · July 24, 2003 1:45PM

None taken

LucyBop · July 24, 2003 1:45PM

picking on a kiddy-o eh, I'll handle you!

DanC · July 24, 2003 1:45PM

Wow... Deja Vu'.

LucyBop · July 24, 2003 1:46PM

hmmm a double post.... thats means your in Double trouble DannyboyC! Grrrrrrr..........

DanC · July 24, 2003 1:48PM

Is it my imagination... or does this Chick keep WINKING at me?

airplanenut · July 24, 2003 1:51PM

Dan,

I agree with you- the larger a picture is if there is any doctoring, and the more it is scaled down, the less evident the doctoring is... that's the point I'm making... basically, if you can make it hardly detectable at 4MP, to reduce it to 12% of its size will make the doctoring just that much less detectable.

Jeremy

MAULDEMALL · July 24, 2003 1:57PM

<< Is it my imagination... or does this Chick keep WINKING at me?

>>

KINDA MAKES YA WONDER DON'T IT................................

Blade · July 24, 2003 1:59PM

Russ,
Wow, ask a simple question...! Thanks for sharing this neat experience. After Dan put some touches on your trick, I have now decided that it would be virtually impossible to peg an image as DCAM from a pic. Guess I'll have to trust the slab again

ursabear · July 24, 2003 2:08PM

<< Can images be manipulated?

>>

OOOOOOHHHHHHHHH! I've been looking for one of those! The rare 1979-S T3!

Great thread, Russ!

coolkarma · July 24, 2003 2:27PM

I agree with the gist of this thread - by manipulating the gamma, you can enhance the apparent contrast of a coin, and it is "child's play" to do this (it takes only seconds). However, this is just the tip of the iceberg. We could learn a lot from professional photographers. Using a "soft" light (e.g., fluorescent) will enhance the contrast, while using a harsh light (e.g., halogen) will decrease contrast, while heightening edges (and scratches). Plus diffuse lighting, and pinhole light sources...

And then there are all those marvelous tools in software like PhotoShop... Small scratch, don't like the color? 15 seconds and its "fixed". And the fix is not detectable in the image.

Because of all the possible manipulations, I think it is very important to describe under what conditions pictures are taken and what if any manipulations were performed. If you know what has been done, then you can replicate the conditions and see what it does to a coin. In an ideal world there would be a standard set of conditions, but...

Richard

K6AZ · July 24, 2003 2:32PM

Better be careful Russ. You may be next to receive nasty PM's from a certain seller.

Dog97 · July 24, 2003 2:59PM

Wow! This thread is scary! Now I see why the dealers are always saying you can't judge a coin from a picture. Of course when people posted coins here asking about the approximate grade I figured they were using honest pictures.
I thought I was pretty good at ciphering pictures but like coolkarma said I just know the "tip of the iceberg."

jonesy · July 24, 2003 7:13PM

I just hope the big auction houses don't do this!!!

northcoin · July 24, 2003 7:29PM

Jonesy - actually it would be against the best interests of the big auction houses to doctor their photos. It would just add to the cost of doing business given the likely increased returns they would get. To add to my point, note how often the verbal descriptions seem to go overboard in describing all the negatives? (for example the oft used reference to a slight scratch or other mark that is described as providing "identification")

dorkkarl · July 24, 2003 9:26PM

<< Sure makes it look like a monster deep cameo. >>

looks more like a cartoon than a cameo to me.

that's why i shy away from stuff like that, i'm not sophisiticated enough to collect those. i'll stick to coins w/ simple grades!

K S

K6AZ · July 25, 2003 1:18AM

<< Jonesy - actually it would be against the best interests of the big auction houses to doctor their photos. It would just add to the cost of doing business given the likely increased returns they would get. To add to my point, note how often the verbal descriptions seem to go overboard in describing all the negatives? (for example the oft used reference to a slight scratch or other mark that is described as providing "identification") >>

Go and look at some of Superior's images.

supercoin · July 25, 2003 3:24AM

It's also very easy to manipulate the cameo appearance of a coin when the photo is taken. I do it all the time with my setup by varying the angle of the lighting backdrop.

It's sometimes a bit of a trick to get right... assuming you're trying to give an accurate idea of what it looks like in real life, of course.

pontiacinf · July 25, 2003 9:15AM

wow

I deffinately want your service now russ

Gamma manipulation and the degree of contrast on cameo coins.

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