Neutral light for Mineral Photography

[zmatt00]

I am a mineral collector and i am trying different things to photograph mineral specimens. Sometimes I need to put a spot of light to backlight a transparent or translucent crystal. Sometimes i want to shine light in a specific orientation relative to the crystallographic axes of the crystal.

I have been trying to find good flashlights for these purposes, and i hoping you could give me some advice on what to buy and where.

One of the keys is a spot beam and a pure white (neutral) light. Mag lights are too warm and it seems a lot of the led lights are too blue. I was lucky when i bought an Energizer Hardcase 2 AAA Inspection Light, because the light turned out to be very white (neutral). This model doesn't focus, so the light is sometimes too dispersed, but the color is good. Sometimes this light puts out too much light for my needs. Interestingly, I just bought another of these and the light was blue tinted! Arrrg! Although the led looks the same (square and flat) they must have changed the LED.

I would really like to get a goose neck model and bought a husky brand gooseneck light from home depot. It is way too blue.

If you have any recommendations for the following, I'd really appreciate it:

1) A small goose neck flashlight with a pure white (neutral) light.
2) A small flashlight with the light at the end of a rigid rod and the light is inside an adjustable swivel housing. This would allow me to precisely position the light behind something I was trying to photograph.
3) Another flashlight like my "old" Energizer Hardcase 2 AAA Inspection Light (bought at Home Depot in Tucson AZ in Feb 2009) which has plenty of power but a really white (neutral) light. I'd prefer one that can really focus the beam.

Thanks in advance for any recommendations you can make.

Sorry if you have already seen this post but I wanted to move this up to see if I can get someone to answer my question.

I am a mineral collector and i am trying different things to photograph mineral specimens. Sometimes I need to put a spot of light to backlight a transparent or translucent crystal. Sometimes i want to shine light in a specific orientation relative to the crystallographic axes of the crystal.

I have been trying to find good flashlights for these purposes, and i hoping you could give me some advice on what to buy and where.

One of the keys is a spot beam and a pure white (neutral) light. Mag lights are too warm and it seems a lot of the led lights are too blue. I was lucky when i bought an Energizer Hardcase 2 AAA Inspection Light, because the light turned out to be very white (neutral). This model doesn't focus, so the light is sometimes too dispersed, but the color is good. Sometimes this light puts out too much light for my needs. Interestingly, I just bought another of these and the light was blue tinted! Arrrg! Although the led looks the same (square and flat) they must have changed the LED.

I would really like to get a goose neck model and bought a husky brand gooseneck light from home depot. It is way too blue.

If you have any recommendations for the following, I'd really appreciate it:

1) A small goose neck flashlight with a pure white (neutral) light.
2) A small flashlight with the light at the end of a rigid rod and the light is inside an adjustable swivel housing. This would allow me to precisely position the light behind something I was trying to photograph.
3) Another flashlight like my "old" Energizer Hardcase 2 AAA Inspection Light (bought at Home Depot in Tucson AZ in Feb 2009) which has plenty of power but a really white (neutral) light. I'd prefer one that can really focus the beam.

Thanks in advance for any recommendations you can make.

 

[Yoda4561]

What you want is a light equipped with a cree LED, in a 3A or 5A tint. These are their neutral white LEDs. There are a number of lights and aftermarket lamps (to replace surefire P60 assemblies mostly) available with 5A leds now. The color sits right in between the blueish LEDs and the yellow-orange incandescent. The best alternative might be one of the nichea high CRI emitters, but those are very hard to find and will require a custom built light. Neither of these is really available in the styles you were looking for, but I'm sure you could get something modified by a builder on CPF to suit your exact needs. For now I suggest looking into the malkoff M60WL and a surefire G2 incandescent, Dereelights cl1h, or perhaps a fenix TK20. The TK20 will be most similar to your hardcase, but a bit bulkier and made out of heavy duty aluminum.

 

[DM51]

Welcome to CPF, zmatt00. Very interesting first post, which would fit in more than 1 sub-forum here.

The problem you will find with most LED emitters is that they are weak in the red end of the spectrum, and over-strong in blue, with somewhat uneven spectral distribution. Incandescent bulbs, by contrast, are weak at the blue end, but provide fairly even illumination in other parts of the spectrum.

Look up "High CRI", and if you don't get bamboozled by all the differing opinions on "tint", "color rendition" etc here, take a look at the McGizmo Sundrop, which is among a very few lights that members here seem to agree does render colors faithfully. It doesn't fit some of your requirements, but it is worth seeing what people say about it.

I said above that this thread would fit in more than 1 forum here, and for the time being I'm going to move it to The Dark Room, our photographic section, as our specialists there may be able to help.

 

[FlashInThePan]

I'll second what the others have said: high CRI (color rendering index) LEDs are a vast improvement and are now beginning to render colors *very* naturally. They'd probably be an excellent choice, and should help your colors come out more naturally. Look for lights made with the Nichia 083 LED, the Cree Q3-5A (or 5B) LEDs, or even some of the high-CRI LEDs made by Seoul. I've used all 3, and the Nichia 083 light is my favorite so far - though they're all a vast improvement over standard LEDs.

Don's Sundrop (Don's also known as McGizmo on these forums) uses the Nichia 083, and it renders colors beautifully. That said, there are a number of people on this forum - TexLight, Milkyspit, etc. - who should be able to help take just about any traditional LED light and replace the emitter with a higher-CRI LED. The cost is usually between $40 and $100, depending on the LED you want and the difficulty of modding the light. I would send them a private message, and I'm sure they'll be able to help you.

Many stock lights are now coming with the warm emitters as well. Right off the bat, I can think of the NiteCore EZAA warm, the Quark "neutral" series by 4sevens (4sevens.com), the Orb Raw (or Orb Wee) by Lummi, Fenix's TK20, etc. You can find most of them for sale at dealers like 4sevens.com, Brightguy.com, and Lighthound.com.

One thing to add: if you're not familiar with the latest lights, you might be surprised by how tiny they can be. None of the lights I previously mentioned has a gooseneck, but a small light might help alleviate the need for a gooseneck - after all, it can probably fit into (or behind, or between) locations that larger lights can't. Of course, there's still the problem of *keeping* the light steady there, so this may not solve the problem entirely...

One final thought would be to pair a small, warm LED light with a flexible tripod. For example, consider the Nitecore EZAA (which has a screw base for mounting to a camera tripod), along with a gorilla tripod or a Flashlight Friend (if it fits).

Hope this helps! Please feel free to post more questions or thoughts; we'll try to help as best we can. Welcome to CPF!

- FITP

 

[ElectronGuru]

The key to what you want to achieve is not in the light source, but the camera. One of these days I'll write a complete tutorial, but here's a quicky:

There is a variety of color neutral photographic equipment, flashes, light bulbs, reflectors & the like. These are cumbersome, limited, and expensive. Trying to create a portable version would only be slightly less (or more) so. I suggest starting with a white balance disc instead. As shown here, calibrate to the specific light source:

http://www.candlepowerforums.com/vb/showpost.php?p=3018691&postcount=30


Then everything illuminated with that light source will appear with the correct color. Control stray light from other sources and color practically calibrates itself. My early testing (circa 2005) showed good results even with something as simple and dim as a single candle.

With this in place, my current favorite is a Malkoff M60W MC-E, which I use in a variety of reflective setups. The bright floody output is perfect for what I'm doing. While this is an LED, incans can be as good or better. WA bulbs, in fact, are designed specifically to backlight a variety of materials in research grade microscopes. And whitebalance discs adapt to these with equal accuracy.

 

[UnknownVT]

One has to be careful here - although those Crees are labeled "Neutral White" - they are far from "neutral" when photographed - especially with fixed daylight white balance.

With photography the closer one gets to true sun/daylight the better off one normally is - even allowing for the use of Auto White balance.

Here are some illustrations - all taken with fixed daylight white balance (Canon PowerShot A610) -

Neutral White vs. regular Cool White -
4Sevens Quark 123-2 Neutral, Tactical, Cool White Comparison Review

see how UN-white both lights are when compared side-by-side?
First the Neutral white (Q3 5A) definitely ain't white when taken with fixed daylight balance -
the regular cool white (bin WC?) is actually a very blue sample -
but this slight exaggeration help illustrate the critical nature when we are talking about colors in photography - something our eyes/brain would probably adjust for, and find more than acceptable - all of a sudden gets revealed as a serious flaw when photographed.

OK how about nicer cool white tints?

Neutral White vs Tactical (regular Cool White)

again the Tactical cool white looks more blue because it is in direct comparison with a warmer Neutral white - but one can see that it is a little less blue than the regular cool white in the standard version - this is probably just variations in the bin.......

Neutral White vs. Fenix P3D-RB100

this Fenix P3D-RB100 (using Philips LumiLEDs Luxeon Rebel LED) has one of my favorite tints for a regular cool white

So for photography - look at the Cree binning chart -
Cool Whites (I borrowed this from this excellent thread -
Bin Coding: Color, Flux, Vf Charts, Links (Luxeon, XLamp, SSC Z-Power/Acriche, Ostar by DFiorentino) -

The typical WC bin is in the color temperature range of 6,300-7,000 degK - this is just too blue for daylight white balance in photography - most cameras are balanced for around 6,000 degK - the ideal range would be about 5,500-6,500 degK which is closer to a WD bin (I personally would prefer WJ - but it might be too warm for photography) -

The problem with LEDs is that even though the binning are reasonable for visual tints - they are just not precise enough for photography - which can be annoyingly too sensitive to tint differences/shifts.

So to get "precisely" the right color temperature and tint one has to work with selecting specific samples and making sure the drive currents are precisely right to get the correct tint (LED tints shift with lower drive currents - the tints and color temperatures are spec'd only for one level of drive current) - all this brings to mind about "guaranteed tints" - by some flashlight vendors - now we are talking about pretty expensive - and even here any slight variation can be unforgivingly revealed by photography that is sensitive to tints/color.

I think zmatt00 got very lucky with that first Energizer Hardcase 2 AAA Inspection Light - the second may just be from another bin or simply tint variation within the same bin! - as one can see with the cool white tint variation examples I gave above.......

 

[blasterman]

Mag lights are too warm and it seems a lot of the led lights are too blue.

If you are using a digital camera and not slide film, why not correct the color temp or try white balancing? Unless you're using a really low end digital camera most have some lattitude in terms of correcting color temp. Or, shoot RAW, if you have that capability - you can then adjust the color temp accordingly after shooting.

If your current camera can't correct out the difference between a cool white LED and a warm white incan, then the problem isn't with the Light you are using, but with the camera. A cool white LED typically has low CRI so colors might be dull, but your camera should still be able to deliver a neutral shoot.

Look up "High CRI", and if you don't get bamboozled by all the differing opinions on "tint", "color rendition" etc here,

An incan light source is very high CRI and is not deficient in blue. The problem is some digital cameras can't white balance below <3000k very well.

The typical WC bin is in the color temperature range of 6,300-7,000 degK - this is just too blue for daylight white balance in photography

If this was 1987 and we were using slide film this would be correct. The only thing that matters to most digital cameras is a color temp between about 3000-6000k and decent CRI. Virtually all neutral and wamr white LEDs have CRI above 80, which should be adequate for the OPs needs. However, if his camera can't handle basic white balancing then fiddling with bin tints won't help. What's neutral to the human eye isn't neutral for a digital camera.

 

[Pontus]

First post.

Have I understood the problem correctly? :

If you're using a digital camera you can set the white balance to match the color temperature of the LED. You will get a colour neutral picture.

Or, you could photograph in RAW mode, and adjust the color temperature in post-processing. Again, you will get an colour neutral picture.

BUT, in order to get a good quality picture you need to get steady light over a broad frequency range (spectral output). You could compare the design problem to good loudspeaker design, which requires a smooth frequency responce over the audible spectrum.

 

[merial]

Better choose any usefull bulb and use white balance to correct the color. The best way is to use custom white balance or shoot RAW.

Im using bulbs and not LEDs bacause LEDs are very weak and not really cheaper. I bought 3 small tabletop lamps with gooseneck and common energy saving bulbs. It is not excellent setup but together it cost about $50. LEDs might be great for shooting under the microscope or super macros but forget about them for specimens over 5 cm. Flashlights are usually quite bad. I did some pictures with external flash equipped with bouncer and some with ringflash but generally my cheap lamp setup provides better results.