Louie Aguinaldo
06-22-2006, 11:18 PM
Just earlier today I was doing a shoot of several fashion items for a magazine. I am always OC when it comes to getting the colors right. And when shooting products, it becomes necessary. Specially for fashion and beauty products, the right color is essential. Anyway, I always make sure that I take a shot of a gretag macbeth color checker under the same lighting that i would use to shoot the products. Thus, when I convert the raw files, I have the color checker as a basis to get the right colors.
Anyway, something really peculiar happened today. There were a set of bags that were made of some nylon type material. The designs were all green fatigue. The strange thing was that no matter what we did, the bags didn't come out green. They all came out gray. Not a tinge of green. I started experimenting changing white balance, trying different color balances, but no matter what we did, the greens came out gray.
So I started worrying that something may have gone wrong with the whole process and so I started to check the earlier images of other products already photographed. All of them were accurate in terms of color. It became very clear that the only problem was with the set of nylon green fatigue bags. What further added to the confusion was that aside from the overall various green shades in the fatigue bags, there were some bright colored accents at some of the edges. What we did notice was that all those accents had accurate colors but the bags themselves still turned out gray instead of green.
What a strange phenomenon. I further inspected the bags thinking that they may be actually gray and just appeared green due to some reflected light or something but after checking, it was clear that they were indeed green. I checked under sunlight, flourescent, and even tungsten and they were green.
Gasp!
I tried checking the images in photoshop and read the rgb values, there was no sign of green but they were gray. Something strange was happening. How could it be that just the colors of the image as a whole be accurate but the green fatigue area was becoming gray.
So, i started investigating further. I then looked closely at the material. It looked like very fine nylon weaved together. Then it dawned on me... could it be that due to the fine nylon patterns, moire' was resulting, and that the moire' itself was causing the color shift in the material from green to gray.
For those not familiar with moire', it is a visual distortion that usually arises from certain closely arranged patterns. These are usually seen in monitors, tv, and digital devices such as scanners and cameras. Some examples would be when you scan or photograph something that had been printed by a printing press. These are usually half tone prints... meaning if you get to magnify your view, you will notice that all parts of the image (even solid colors) are actually made of tiny dots of color. In between the dots are tiny spaces. It is the pattern here that causes moire. Thus when you scan it or photograph it you would often find some strange distortion.
Moire' also happens on tv, if you happen to see something on tv like a fine striped shirt you will see some distortion almost as if there movement between the stripes.
Anyway, I figured, could there be a strange moire pattern resulting from the fine nylon weaves and that this was causing the strange distortion in the form of a color shift from green to gray? So i started playing around by moving and angling the bags in the light and photographing them. Most of the time, no matter where I angled it, it still turned gray. Until at one point , I did a really weird angling of the product in relation to the light and there I saw the phenomenon split in two. Most of the bag was gray but there was a portion of the bag that was green. the distinction was so clear, it was if there was a line between the two portions.
Wow, we learn something new everyday.
Still not sure exactly, but so far the only theory I could think of is moire'. I wanted to experiment further but time was up.
Well, if anyone has any theories with regards to the phenomena, i'm all ears.
I would have wanted to show the sample images but since they are to be coming out in the magazine, I can't for the time being.
Anyway, something really peculiar happened today. There were a set of bags that were made of some nylon type material. The designs were all green fatigue. The strange thing was that no matter what we did, the bags didn't come out green. They all came out gray. Not a tinge of green. I started experimenting changing white balance, trying different color balances, but no matter what we did, the greens came out gray.
So I started worrying that something may have gone wrong with the whole process and so I started to check the earlier images of other products already photographed. All of them were accurate in terms of color. It became very clear that the only problem was with the set of nylon green fatigue bags. What further added to the confusion was that aside from the overall various green shades in the fatigue bags, there were some bright colored accents at some of the edges. What we did notice was that all those accents had accurate colors but the bags themselves still turned out gray instead of green.
What a strange phenomenon. I further inspected the bags thinking that they may be actually gray and just appeared green due to some reflected light or something but after checking, it was clear that they were indeed green. I checked under sunlight, flourescent, and even tungsten and they were green.
Gasp!
I tried checking the images in photoshop and read the rgb values, there was no sign of green but they were gray. Something strange was happening. How could it be that just the colors of the image as a whole be accurate but the green fatigue area was becoming gray.
So, i started investigating further. I then looked closely at the material. It looked like very fine nylon weaved together. Then it dawned on me... could it be that due to the fine nylon patterns, moire' was resulting, and that the moire' itself was causing the color shift in the material from green to gray.
For those not familiar with moire', it is a visual distortion that usually arises from certain closely arranged patterns. These are usually seen in monitors, tv, and digital devices such as scanners and cameras. Some examples would be when you scan or photograph something that had been printed by a printing press. These are usually half tone prints... meaning if you get to magnify your view, you will notice that all parts of the image (even solid colors) are actually made of tiny dots of color. In between the dots are tiny spaces. It is the pattern here that causes moire. Thus when you scan it or photograph it you would often find some strange distortion.
Moire' also happens on tv, if you happen to see something on tv like a fine striped shirt you will see some distortion almost as if there movement between the stripes.
Anyway, I figured, could there be a strange moire pattern resulting from the fine nylon weaves and that this was causing the strange distortion in the form of a color shift from green to gray? So i started playing around by moving and angling the bags in the light and photographing them. Most of the time, no matter where I angled it, it still turned gray. Until at one point , I did a really weird angling of the product in relation to the light and there I saw the phenomenon split in two. Most of the bag was gray but there was a portion of the bag that was green. the distinction was so clear, it was if there was a line between the two portions.
Wow, we learn something new everyday.
Still not sure exactly, but so far the only theory I could think of is moire'. I wanted to experiment further but time was up.
Well, if anyone has any theories with regards to the phenomena, i'm all ears.
I would have wanted to show the sample images but since they are to be coming out in the magazine, I can't for the time being.