# Photographing item with dual tone (e.g. black and pink pistol)



## amadaras (Mar 27, 2014)

New to the forum, so I am not sure if I am posting this in the correct location. Anyways, be kind. 

I am a product photographer for a local company that sells airguns. While most items I can photograph very well, I always struggle with items that have a high contrast in color. We have some guns that are dual tone (black and silver, black and pink, black and green, etc) and I have a hard time finding balance. The blacks are always very black, and the bright colors are always blown out.

I have a very simple setup; two hotlights with umbrellas, and some reflectors. The camera I work with is an old Canon 50D. The tripod is... crap.

While I normally would just use a multiple exposure to expose each area correctly, my tripod is not the most stable and will move between shots (more than just a little bit), making multiple exposures next to impossible.

Any tips or tricks to help me out?
Thanks!


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## hotdrop (Mar 27, 2014)

Remote Triggers will help if you want to do multiple exposures or continuous shooting to turn off lights, unless the tripod drifts or the shutter movement actually shifts the image (you could shoot a target in the corner if you really want and adjust you image such that the target is consistent as well then crop it out). Another thing you can do is mask out the light to the areas you don't want to over expose using a Piece of glass covered with black tape in the rough shape of the highlights then position it such that it is just outside the FOV of the camera in the direct path of one or both of your lights. Do you have any pictures you can share of things that got blown out?


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## Gavjenks (Mar 27, 2014)

> While I normally would just use a multiple exposure to expose each area correctly, my tripod is not the most stable and will move between shots (more than just a little bit), making multiple exposures next to impossible.


I think you just answered your own question there.


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## Scatterbrained (Mar 27, 2014)

As I posted in your other, duplicate thread, how about showing us both your set up and a shot you're having issues with.    This can be done in one exposure if you know how to place your lights and flags.


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## Gavjenks (Mar 27, 2014)

If the reflectance of the black and non-black parts of the guns are more stops different than the dynamic range of his camera, then it may not be possible (without something like attempting to light different parts separately, which depends on how the two-toning is arranged on the piece as to whether it is feasible). Multiple exposures may be easiest. or potentially necessary in extreme cases. Although feathering light may also work, if the pink color is all on one side or all on the top of the gun or something.

Oh do make sure though that you're shooting at *ISO 100*. You have the greatest dynamic range at your low ISOs. If you're at 400 or something you might be losing two or more stops of your dynamic range, potentially, and that could be the entire source of the problem right there.


(Also no matter what solution turns out to be easiest, you need to replace a tripod that frickin' moves across the room from a shutter actuation (!) That's just ridiculous)


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## Scatterbrained (Mar 27, 2014)

I disagree.  It's all about being able to control your light; using diffusers, reflectors, flags, scrims, gobos, what have you.













It's all about using the appropriate tools to control the light.


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## Gavjenks (Mar 27, 2014)

That's some nice lighting, yes, but which of those pieces of equipment exactly is responsible for reducing the dynamic range between the black and white internal seams/edges in the middle of the shoe? I'm pretty sure none of them. If the two were 20 stops apart in reflectance, you'd still have to take more than one exposure or have blown out highlights or blocked shadows. The shoe just simply didn't have too much dynamic range for your camera.


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## Scatterbrained (Mar 27, 2014)

The shoe is gloss white and black.  Doesn't get much farther apart than that. The dot keeps the white from blowing out, the mirror lifts the blacks in the sole.   That's the point.   The watch is polished stainless steel, brushed stainless, and matte carbon fiber.  Pretty high contrast range.     Aside from that, exposure is exposure.  If you meter the light at f/5.6, whatever you put there will be properly exposed at f/5.6.   Highly reflective subjects (i.e. polished materials like the watch) being the exception, where you are shooting the reflection and not the material itself. Even then it's not an issue of adding more light, it's an issue of putting the diffusion material or reflector where they will fill the angles of reflectance relative to the camera.    This isn't rocket science you know.


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## Gavjenks (Mar 27, 2014)

We are just talking about different things, I think. You're talking about regions, like a shadowy sole area of the shoe that would be indirectly lit if not for a mirror. I'm talking about sharp edges, that can't possibly be lit differently because the change happens in a 1/10th of a millimeter (there are common materials with much higher and lower reflectances than shoe pleathery stuff, or than carbon fiber and brushed metal. Especially if the pink in the guns is fluorescent, in which case it can "reflect" more than 100%! Which I've seen before)

Anyway, in all likelihood it's probably both things and any of the above solutions alone would be enough to solve it, and the OPs question has been answered many times over.

I just find hypotheticals like this fascinating, no offense (the product photos are fantastic). In this case, the question "Are there common materials that would have such a high reflectance difference that if they formed a single flat edge together, modern cameras simply cant capture them?" I think the answer is "no" for something like a D800 used at its optimal 100ISO, but probably "yes" for a 50D used at say ISO 400 by somebody who might not know better. Whether that's going on here, no idea.


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## Scatterbrained (Mar 27, 2014)

Take a look at the shoe.  It's gloss white and jet black.  The only reason the dot was needed for the heel was because the heel was closest to the light, therefore it was brighter (inverse square law and all that).   At full resolution the shoe has detail in the whites and detail in the blacks, which was my point.  If the meter says the light is f/5.6, then at f/5.6 you'll get a correct exposure.  It doesn't matter what color the item is.  At f/5.6 it will be rendered accurately.  

When it comes to reflectance DR has nothing to do with being able to capture the scene.  What matters is lighting it in a way that the light source is reflected into the camera.  Working in a controlled, studio setting DR simply doesn't matter.  A camera phone has all the DR you need in a studio.   What matters in a studio camera is resolution (both MP and outright detail resolving ability) and color.


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## Scatterbrained (Mar 28, 2014)

Amadaras, I don't own any air pistols, so I grabbed the only gun I have that remotely fits the description of what you're dealing with.    It's semi-polished stainless steel with an anodized black grip.  The lighting set up for this is actually quite simple and works far more often than it doesn't for most small products.  Granted the set-up I've used is a bit more complex, but even without the extraneous flag, finger, reflector, and mirror the set up will work, it just requires a bit more burning in post.  Of course if you're shooting on white then that wouldn't even matter.  

Single light from behind the subject through a sheet of vellum (drafting paper) that's been pulled over the set.   Black foamcore as a flag to knock down the light hitting the top of the set above the pistol.  White reflector under the camera to bring white reflections back into the lower front side of the pistol.   Strip of black Cinefoil on the reflector to break up the white reflection on the barrel.  Mirror on the lightstand camera left to bring some hard light in across the gun, providing a highlight down the back of the gun and some texture to the grip.   Finger scrim under the vellum to knock down the light on set camera left.  High camera angle with long focal length to both reduce perspective distortion and minimize the angles of reflectance I have to fill to get a white reflection across the metal.  
















And just to cover any concerns about pink :mrgreen::


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## Gavjenks (Mar 28, 2014)

Scatterbrained said:


> Take a look at the shoe.  It's gloss white and jet black.  The only reason the dot was needed for the heel was because the heel was closest to the light, therefore it was brighter (inverse square law and all that).   At full resolution the shoe has detail in the whites and detail in the blacks, which was my point.  If the meter says the light is f/5.6, then at f/5.6 you'll get a correct exposure.  It doesn't matter what color the item is.  At f/5.6 it will be rendered accurately.
> 
> When it comes to reflectance DR has nothing to do with being able to capture the scene.  What matters is lighting it in a way that the light source is reflected into the camera.  Working in a controlled, studio setting DR simply doesn't matter.  A camera phone has all the DR you need in a studio.   What matters in a studio camera is resolution (both MP and outright detail resolving ability) and color.


It might not matter ENOUGH to screw you up, depending on your ISO and camera, but of course it matters.

Hypothetically, let's say you have an edge:
Black side = 0.5% reflectance
White side = fluorescent material with 175% reflectance

You can't light them differently, because they are right next to each other. So whatever light you shine will hit both equally. The two surfaces have a difference of 8.5 stops, so if your camera at current settings has only 8 stops of dynamic range, it will either blow out the highlights or the shadows even *AT *perfect metering. Imperfect metering will simply make one of those even worse.

If you shoot 200 photons of visible (and 200 photons of UV, all flashes) at it, then you'll get back 1 photon and 175 photons respectively, i.e. 8.5 stops
If you shoot 4000 photons of each at it, then you'll get back 20 and 3,500,* still 8.5 stops
*
So no matter what strength your lights, it's still beyond your camera's range, and no matter what setup, the edge is instantaeous and impossible to light separately




Your images don't really accomplish anything with regard to this, because simply being pink doesn't have anything to do with reflectance, your gun you have there is brushed nickel or something which is utterly different reflectance than polished chrome, say, etc. etc. AND you probably have a much better camera than the 50D AND the OP might be using it at a higher ISO


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## Scatterbrained (Mar 28, 2014)

Digital cameras have both IR and UV blocking filters over the sensors these days.   Of course, if that's not enough you could always get a UV filter for your lens, you know,_ for protection_.  Of course, there's also polarizing films and filters that can be used both over the lights and on the lenses to further control the lights/reflections. . . . . . . .


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## Gavjenks (Mar 28, 2014)

Scatterbrained said:


> Digital cameras have both IR and UV blocking filters over the sensors these days.   Of course, if that's not enough you could always get a UV filter for your lens, you know,_ for protection_.  Of course, there's also polarizing films and filters that can be used both over the lights and on the lenses to further control the lights/reflections. . . . . . . .



I said fluorescent material. Fluorescence means material that absorbs UV light and then converts the radiant energy into emitted visible light instead, thus appearing to "reflect" (actually a combination of reflectance + chemical emittance) more visible light than the amount of visible light hitting it.

Thus, by the time it reaches your lens or sensor, it is all visible already, not UV anymore, and UV filters are irrelevant.  (You could put a UV absorbing gel on the flash, yes, which would be a solution if that were the case, but probably expensive and difficult to find for a 4 foot softbox)

That's why dayglow hunting vests, or liferafts, for instance, appear so unnaturally bright orange to your eyes: More then 100% of the visible light hitting them is coming off of them as visible light, because a lot of the UV is also being converted on the surface. Your retinas can't see UV either, just like your camera can't see it very well. But that doesn't matetr because it's visible already when it gets there.


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## Scatterbrained (Mar 28, 2014)

You're trying really hard here.    You do know that going up a stop _doubles_ the amount of light right?  Meters measure to medium gray (18%).  Rule of thumb is, two and a half stops up will give you white and four and a half down will render black.  You're talking about a difference of less than one full stop.  Not an issue.   As a matter of fact, I just took my florescent safety vest that I wear when riding my motorcycle at night, and put it under the gun (in place of the tiles), imagine my surprise when the image came out just fine.


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## Scatterbrained (Mar 28, 2014)

Just to show you what I'm talking about,  here's my dayglow, military spec safety vest under the gun, along with the histogram:









Notice the spike to the right?  It's brighter, but it's nowhere near clipping, and that's after my tone curve has been applied.  With the default, flat tone curve it wasn't quite as far out to the right.


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## Gavjenks (Mar 28, 2014)

> You're trying really hard here. You do know that going up a stop _doubles the amount of light right?_


Yes, see previous example

*Reflectance in my earlier example*
0.5% doubles to  [same stuff as at 2%, but inside of a groove or decoration or overlap of metal]
1% doubles to  [black velvet would be around here]
2% doubles to [really matte really black coatings like rubberized stuff, or paint used inside lens barrels, etc.]
4% [normal flat black paint]
8%
16% [black matte basic plastic like the coffee machine handle is probably around here at 5 stops]
32% [brushed nickel probably around here at 6 stops maybe 1 higher]
64%
[highly polished chrome highlights around here somewhere at 7.5 stops]
128%
[fluorescent could be around here somewhere at 8.5 stops]
256%




> As a matter of fact, I just took my florescent safety vest that I wear when riding my motorcycle at night, and put it under the gun (in place of the tiles), imagine my surprise when the image came out just fine.


Yeah, again... you probably have a much nicer camera than a 50D and you're probably using it optimally at ISO 100. So something that might just go beyond the capabilities of a 50D used at high ISOs (as it very well might be since OP is using continuous lighting and may not know that ISO matters) is just a slam dunk for you, potentially.

For example, the dynamic range of a 50D used at high ISOs can be about *6 stops lower *than the capable range of a D800 used at its lowest ISO.  So yeah, depending on what you have, *you *might be able to photograph NASA's best space-age white and black materials at 12 stops apart or something, but that doesn't mean *he/she* can do the same things you are doing.



That's why I said way earlier "Is there an edge that can't be captured no matter what lighting? No for a D800, probably yes for a 50D." A difference of 8 or 9 stops might cause an older smaller sensor camera to fail no matter what, whereas a new full frame eats it for lunch. Even more extremely, an early generation micro 4/3, or maybe a cell phone camera might UTTERLY FAIL to be able to possibly capture the shoes that you captured quite easily (even though those are probably more like 4 stops)


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## Scatterbrained (Mar 28, 2014)

Once again you're thinking about this the wrong way.  If you are supplying the light, DR doesn't matter.  Period.  You control the range of the scene.  That's the whole purpose of using a light meter and shooting in a studio.  BTW, that shot was a 5DII, same generation of sensor as the 50D, but it would work just fine with a camera phone.   The DR of that scene is only a few stops.  The lighting on that scene doesn't vary by more than 3 stops across the whole frame.  People have been achieving shots like this since long before the D800 came out.   Dynamic range is a luminance issue, not a color or tone issue.  Something that is black, when properly exposed, will still be black.  Something that is white, when properly exposed, will still be white.   Your argument is predicated on the assumption that you're trying to illuminate everything to the same tone, which would simply render a grey image.   Have you ever used a handheld lightmeter?   A lightmeter takes a reading of the light falling on the scene and tells you what camera settings to use to render the scene correctly.   An accurate reading will give you camera setting that will render black as black, white as white, and grey as grey.  That's the point.  If a subject has a matte surface, that surface will render matte under the light.  With highly reflective, polished items you're shooting for the reflection; but again, DR doesn't matter, light placement does.


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## Scatterbrained (Mar 28, 2014)

Okay, just went and shot it with my little M P&S (same sensor tech as the 50D BTW).   Shot came out just fine.  I also tested the Dynamic Range of the scene with my light meter.  1 stop.  I can't imagine there's a camera in the world right now that can't handle that.  From f/5.6 +.9 to f/8 +.9.  





Dynamic range is about_ light_, which is why it's always discussed in terms of _highlights_ (bright areas receiving a lot of light) and _shadows_(areas receiving little relative light).


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## Gavjenks (Mar 29, 2014)

> Once again you're thinking about this the wrong way. If you are supplying the light, DR doesn't matter. Period. You control the range of the scene. That's the whole purpose of using a light meter and shooting in a studio.


This is simply incorrect. I'm not really sure how else to explain it.  I will try once more:

Imagine just a rectangular rod sitting on a table. It is split half and half, one half is a material that reflects 4x as much light (2 stops more) as the other side. There is a sharp boundary in the middle.

You can use multiple lights or whatever to light the two ends of the rod differently, yes, but the boundary right at the very middle where it switches over, it goes from dark to light in just a single pixel's worth of your sensor. Those two pixels will have pretty much the exact same amount of light hitting the amount of the rod that each one represents.
No matter how fancy your lights are, this is going to be true for those two pixels.
No matter how bright your lights are, this is going to be true for those two pixels.

Let's say the number of photons that hits each of those pixels during an exposure is 100 photons (speaking in terms of ones that would hit your camera if not absorbed). The black side pixel will reflect 10 of those photons perhaps, the white side pixel will reflect 40 of them. A 1:4 ratio

*This same ratio holds no matter what the hell you do with your lighting setup. *Use 15 lights, use 1 light. Use flags, scrims, dots, softboxes, umbrellsa, CFC bulbs, candles, bonfires, bioluminescent bacteria in a box. Whatever. NONE of them are going to have much of a significant difference in luminance from one of those pixels to the other pixel. The only effect you could possibly have would be the amount of feathering of a light that occurs over a single pixel's distance, which is of course negligible.

*Also, the same ratio holds no matter what strength lights you use.* Expose 200 photons instead? It becomes 20 reflected and 80 reflected (still 1:4 ratio). Expose 5,000,000 photons instead? Becomes 500,000 and 2,000,000 reflected (STILL 1:4 ratio). 

So that one edge there in the middle of the bar *guarantees *that the dynamic range of the scene will be *at least* a ratio of 1:4, or 2 stops in that example. Completely regardless of any lighting decisions you make at all. It might be higher than that (if, say, the black side is in shadow and the white side is more lit)! And to the extent it is, you could reduce it by changing your lighting setup to more even lighting, say, or even reverse lighting. But all you can ever do by that is reduce it back down to 2 stops minimum, if an edge like that exists in the scene.

Here is a diagram:




Initial light in middle. 
Cranking up the general ambient lighting by 2x does nothing to the ratio.
Cranking down the general ambient light by 2x does nothing to the ratio.
Shining a light on just the middle area does nothing to the ratio at the critical edge, and actually increases total scene DR.
Shining a light in a vain attempt to light only the dark side still bleeds over a tiny bit and does nothing to the ratio at the critical edge.

*NO MATTER WHAT you do with lighting, it will be guaranteed at least 2 stops DR in the final image due to that edge being 2 stops of reflectance difference.* (a perfectly sharp cutoff of light on one side versus the other is not possible, because in real life, it's not a straight single line. It's crazy stuff like shoe patterns, that you have no chance of matching).

And if the difference at the edge were 9 stops reflectance, the scene would be guaranteed to be at least 9 stops DR no matter what.

(the 1.98 stops for example is due to the feathering being enough to slightly change light intensity from one side to the next. This is exagerrated in the diagram though, since it's only a few hundred pixels wide, not 5,000 or so like most DSLRs. In a photo, this effect would thus be cut down by a lot, and it would be closer to just 2, period.)





In fact, I'd go so far as to say it is a general rule that the minimum boundary of the dynamic range of any scene is going to be mostly *defined *by the number of stops' difference between reflectance values for the highest contrast single surface edge in the scene.


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## Scatterbrained (Mar 29, 2014)

Until you find this mythical "thing" it's just mental masturbation.   I've posted examples that have met all you objections and received nothing back but more conjecture.   Find this mythical rod and I'll photograph it for you.    I've given you a scene with both polished stainless steel, matte black, dayglow, gloss black, etc, and it all fit nicely in the jpeg histogram with room to spare.    I have photographed for you things you said couldn't be done.  Now it's your turn to put the camera to work.


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## Gavjenks (Mar 30, 2014)

Look, I was simply hoping to have an interesting hypothetical discussion about what is a pretty cool logical consequence of the physics of light and materials. You've made it clear though that either you don't understand what I'm talking about (whether it be a failure of my describing it or otherwise), or you would understand but aren't reading closely, or you're just being belligerent. In particular, listing "matte black" in the same list as stainless steel as if those were equivalent or similarly relevant terms for this discussion...

Regardless, I guess I don't really care anymore, because one way or the other, it's obvious that the discussion isn't going to be had here, so I'll go ask at the next vision researcher reading group meeting at the office instead, where I know people will care about imaging theory for theory's sake.

Thanks for sticking with me up til here.


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## Scatterbrained (Mar 30, 2014)

I know exactly what you're saying.  Basically, that something reflective will create a highlight, that highlight will exceed the DR of the camera and therefore can't be photographed.   You're assuming that an image with a wide tonal range will require a camera with more DR.  What I have _demonstrated_ for you is that it can still be photographed, with any camera, so long as you know how to light it.   Sure, if you shine a light into a mirror you're going to get 100% of that light back, that's why you don't shine the light straight into the mirror     What you don't seem to be wrapping your mind around is that when something is highly reflective you don't shine your light into it, you choose what will be reflected in it instead.


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