How to photograph backlit translucent rocks?

[jamesp]

Some of this coral has great color. It is washed out by 'Phillips Natural Light 50 watt flood lamp' to the yellow orange direction.
Even if the stone appears deep purple/red in real time. The last two are about colorless and show little yellow/orange.??
Would shooting them with a sunlight background do better?

[Drummond Island Rocks]

those shots look great James. For tumbles I usually do like you are doing and hand hold in front of a bulb but for thinner items like cabs I use a nifty little lexan tracing light box my wife had for another craft/hobby.

here's a couple shots of cabs with it
forum.rocktumblinghobby.com/thread/64037/1-28

And this is pretty much what it is. Its a frosted white lexan box with a bulb in it.


Chuck

[grayfingers]

James, I sometimes put a brooder light with a flood lamp in a box with a hole cut for the cord. I set a glass platter from a microwave over it, and tissue or paper over the glass. Then I light from above too.

[jamesp]

And this is pretty much what it is. Its a frosted white lexan box with a bulb in it.

Read more: forum.rocktumblinghobby.com/thread/64213/photograph-backlit-translucent-rocks#ixzz2seal0PIQ

James, I sometimes put a brooder light with a flood lamp in a box with a hole cut for the cord. I set a glass platter from a microwave over it, and tissue or paper over the glass. Then I light from above too.

Read more: forum.rocktumblinghobby.com/thread/64213/photograph-backlit-translucent-rocks#ixzz2seaqk0df

You guys are genius. That looks like the way. Thanks. I am glad there are others that like to show off their stuff.
The cabs are fine looking Chuck. And the Montanas are Montanas Bill, in a class to their own.

[pghram]

James,

Here is a before & after comparison of an agate cab.





Rich

[Drummond Island Rocks]

Here's a better shot of the one my wife is letting me borrow from her craft area.



If you google "embossing light box" they will come up. Not sure if its bright enough for thick tumbles but it works nice on cabs.

Chuck

[pghram]

Grayfingers,

That produced oustanding results, thanks for sharing you process.

Rich

[jamesp]

Did this real quick in the sun light. It still looks oranger than it's purple ish color. Is not the sun heavy w/orange colored light?

But i think the sun is richest in the orange spectrum. There are all different colored stars.
The hottest being white to blue, the coldest being red. The middle being yellow.
Am i talking greek? Do i need to try a 6000K real hot white bulb maybe?
I want to have a strong pure white source that penetrates.

[jamesp]

Here is a before & after comparison of an agate cab.

Read more: forum.rocktumblinghobby.com/thread/64213/photograph-backlit-translucent-rocks#ixzz2semmLC2X

Rich, try holding other colored translucent agates like you did there in the sun like lavender, purple, red if you have such,
to see if you have a strong orange color component.

It may be that the color is derived from iron and the iron goes orange. But i am pretty certain the sun light has a peak in the orange color.
Like when you look at the sun(not long please) or a child paints it. It's always orange.

The orange is bothering me. But i do not know the science of light color. Only heard enough to put me in a quandary.

A pure white light source. Does that exist? Or is the sun a pure white light source? Or are our eyes set at the white balance of sun light?
Or am i going wacko .

[pghram]

James,

I just took a couple of snaps of an amethyst cab for comparison.





Rich

[gemfeller]

Feb 7, 2014 12:14:22 GMT -5 jamesp said:

A pure white light source. Does that exist? Or is the sun a pure white light source? Or are our eyes set at the white balance of sun light?
Or am i going wacko .

James, maybe this will help: lowel.com/edu/color_temperature_and_rendering_demystified.html

In general midday sunlight has more blue than incandescent light which is strong at the red end of the spectrum. (Sunlight is also reddish at dawn and sunset.) This affects the color of images unless it's compensated for with white-balancing your digital camera or using proper film.

I think white light is defined as light perceived by the eye as having the same color as sunlight at noon.

[jamesp]

Feb 7, 2014 13:34:32 GMT -5 gemfeller said:

Feb 7, 2014 12:14:22 GMT -5 jamesp said:

A pure white light source. Does that exist? Or is the sun a pure white light source? Or are our eyes set at the white balance of sun light?
Or am i going wacko .

James, maybe this will help: lowel.com/edu/color_temperature_and_rendering_demystified.html

In general midday sunlight has more blue than incandescent light which is strong at the red end of the spectrum. (Sunlight is also reddish at dawn and sunset.) This affects the color of images unless it's compensated for with white-balancing your digital camera or using proper film.

I think white light is defined as light perceived by the eye as having the same color as sunlight at noon.

This is part of the subject i wanted to get into. I apologize for going full circle to get there.

The definition of white light. Noon light w/blue sky back ground. And then noon sun on an overcast day.....what impact is that?

[jamesp]

I have noticed Tela, Chuck and George have very white photos.

I see Chuck's curly Q fluorescent bulb through the reflection in his dang shiny rocks.

George posted a piece of petrified wood that is dead white. Hungarians have abnormally large brains and are very smart
I believe he said they are fluorescent 23 watt 6500K bulbs. It was my favorite photo. Here it is:

quote author="GeorgeStoneStore" source="/post/724372/thread" timestamp="1391354296"]sample photo, shot Sony HX100V. petrified wood , from Hungary.
Location: Megyaszó, Zemplén Mts

( light source, two compact fluorescent lamp, 6500K, 23W, camera tripod, self timer)
[/quote]

[unclestu]

Here is a link to get 5500K flourescent photo bulbs. Regular bulbs are to warm a color temperature temperature causing a redish tint. These bulbs will provide the light to get accurate colors without the need for filter correction. They have a 10,000 hour lefe and use lettle eectric and produce leittle heat
Stu

[jamesp]

Feb 7, 2014 16:57:00 GMT -5 unclestu said:

Here is a link to get 5500K flourescent photo bulbs. Regular bulbs are to warm a color temperature temperature causing a redish tint. These bulbs will provide the light to get accurate colors without the need for filter correction. They have a 10,000 hour lefe and use lettle eectric and produce leittle heat
Stu

Did you forget the link Stu ?

[jamesp]

Feb 7, 2014 12:30:34 GMT -5 pghram said:

James,

I just took a couple of snaps of an amethyst cab for comparison.





Rich

The sun made a great photo of that amethyst Rich. No orange or yellow. Must be a color issue once light passes thru the coral. The agate cab looks
about what color it should be w/light passing thru it. Being whisker colored. Nice pieces.