Talking about lighting.

[Leonardo]

Hi everybody!

I will try to give you some technical tips about lighting from my best knowledge… and English language!

-At noon, in a sunny day, we have about 100,000 lux. This is a highest amount of natural light and the human eye is prepared to drive this level perfectly. So, no matter what quantity of lighting bulbs we have powered on, we cannot reach this level in a house or shop.

-The more difficult task requires more light. It is easy to find levels about 15,000 to 25,000 lux in an Operating Room in a Hospital.

-Indirect light eliminates the shadows. Also a frozen filter smooths the light bean providing a more comfortable illumination.

-The microscope optics lenses reduce the amount of light that effectively reaches the eyes. So, the more power optics would need even more lighting.

-For the engraving work, a level of lighting about 2,000 to 5,000 lux would be desirable.

-As a reference, a 36W fluorescent lamp setting about 1.5-1.7 meters over a table will give to us about 200 lux ON the table.

-The lighting level obtained on a surface is inversely proportional to the distance from the light source and this relation is quadratic; in other words, if we move the light source to the double distance we will have one quarter of the effective light on the surface. This is valid for the cameras flashes too.

-If we are working in a highly illuminated area, it is desirable to have a well-illuminated room too, to prevent being dazzled when changing from one point of view to another.

-Better color reproduction is obtained with warm lighting lamps.

-The highest human eye response (definition) is about 550nm (nano-meters), which is an orange-like color emitted by the sodium lamps but… the worst color reproduction is obtained in this wavelength.

Note: 1 FC (one candle by square foot) is about 10 lux. For example: 10 footcandles are about 100 lux.
When you are choosing a lamp or a lighting fixture, the power would be specified in lumens (!!!???). We have one lux when, on a one by one meter surface fall the light projected from one lumen source at one meter of distance; 1 lux is equal to 1 lumen per square meter (1 lm/m2). The difference between the lux and the lumen is that the lux takes into account the area over which the luminous flux is spread.

I have attached a guide scanned from a General Electric Lighting Estimator.

Hope this help! Leonardo.

 

[ArtisanAttributes]

Thanks Leonardo, for a very informed and non-negative reply to a genuine inquiry.

 

[Lee]

Thanks Leonardo. Now if I'm smart enough to do something with this. I read another thread and see there is another Lee. I am me and he is he.

I use a ring lamp and sometimes wish for more or different lighting and read with interest different solutions people are exploring. Thanks for the responses. Pictures of the unconventional ones would be very helpful. I'm liable to try some.

 

[Leonardo]

You all are welcome. I was very far from the intention of starting a dispute. So sorry about that.

When I am looking for quality and scientific optics components I use to buy from Edmund Optics. There are no cheap products there but of high quality. Here is the link:

http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=1322

and also you can see at these page for a very interesting information about lighting an filtering:

http://www.edmundoptics.com/techSupport/DisplayArticle.cfm?articleid=264

Best regards, Leonardo

 

[Marcus Hunt]

wow, thanks for that info Leonardo. Some extremely interesting links there!

 

[Glenn]

Great thread! Nice learning opportunity.

 

[John B.]

Leonardo, many thanks for the wonderful information about lighting.
Best regards, John B.

 

[Powderhorn]

In the other thread on lights and headrests: I wrote that I used a fluorescent ring light, and a flex arm with a 100 w floro bulb. For a little more info , I am using a Stocker-Yale 12 watt ring light, mounted on the scope. Also I use a flex arm drafting type light with a 100 watt fluorescent daylight bulb in it, gives lots of light and stays cool. The flex, I position to the side so that I get plenty of light with no reflection up into the scope. I found that I could see the patterns better with the angle light, than just the ring light.

 

[Sam]

Thanks Leonardo! I added your post to the Tips Archive. / Sam

 

[Leonardo]

Thank you all. I like that you have appreciated this info and hope it will be helpful.
Yes powderhorn, you are right, the light flux grazing a surface enhance the surface relief bringing out the works details.
Cheers,
Leonardo

 

[CJ Allan]

Thanks Leonardo........Great Info..

and thank you too Powderhorn.........
You have answered several questions for me....
The headrest being the best .....Now I'm in the process of makin one.....
I discovered this one item ,or lack of, is the biggest reason I could never get used to my scope..
Where did you find your Stocker-Yale 12 watt ring light ....??

I guess the biggest thing with ring lites is to get a 12 watt one.......8 ain't enough....

.......cj

 

[Powderhorn]

CJ: I would watch Ebay, as the new ones are expensive to buy. Watch out for the china knockoffs, there no good. I got mine with my scope. You should be able to pick one up for less than $50.00.
If you need more info, or a parts list for the scope headrest, let me know.