So are AB tubes UV coated or not

vadim_c wrote in post #8327149
Did you change modifiers ?

Nope. Been using the same large softbox and stripbox for a while now.

Photon Phil wrote in post #8327230
can you tell which tubes are coated by looking? Perhaps a special "glare" to them when looking at light reflecting off of them? My AB about a year to year and a half old , are those the "old" ones?

Not sure. Mine are pretty old, so maybe I'm getting to the end of life on them.

AxxisPhoto wrote in post #8327276
Not sure. Mine are pretty old, so maybe I'm getting to the end of life on them.

A good excuse to order new flashtubes that are coated

vadim_c wrote in post #8322497
http://www.alienbees.c​om/features.html
Does not say it is. I would be surprised if marketing people at AB missed an opportunity to boast with yet another feature.
However the replacement tubes are UV protected:
http://www.alienbees.c​om/tubes.html

Unless you are using it with absolutely no light modifiers in front of it, it makes no difference as the fabric in the softbox, umbrella or brolly will absord any and all UV light.

Benji

Benji wrote in post #8329621
Unless you are using it with absolutely no light modifiers in front of it, it makes no difference as the fabric in the softbox, umbrella or brolly will absord any and all UV light.

Benji

True. I honestly don't think the tubes are actually 5600K balanced.

Benji wrote in post #8329621
Unless you are using it with absolutely no light modifiers in front of it, it makes no difference as the fabric in the softbox, umbrella or brolly will absord any and all UV light.

Benji

Are you sure ?
Many synthetic materials start emitting their own light when exposed to UV rays and it is rather rule than exception that cheap modifiers do not use more expensive materials that do not do that.
Check for example here:
https://photography-on-the.net …e/index.php/t-476563.html

vadim_c wrote in post #8330469
Are you sure ?
Many synthetic materials start emitting their own light when exposed to UV rays and it is rather rule than exception that cheap modifiers do not use more expensive materials that do not do that.
Check for example here:
https://photography-on-the.net …e/index.php/t-476563.html

So what. It really doesn't make one iota of difference provided you do a white balance of the light before shooting. If the fabrics Paul C. Buff used adds some UV, a simple click of the white balance tool in ACR will correct it. Why anyone would gel it like he suggests is beyond me.

I'm amazed at some of the nonessential junk in digital photography that some people worry about.

Benji

Benji wrote in post #8331028
So what. It really doesn't make one iota of difference provided you do a white balance of the light before shooting. If the fabrics Paul C. Buff used adds some UV, a simple click of the white balance tool in ACR will correct it. Why anyone would gel it like he suggests is beyond me.

I'm amazed at some of the nonessential junk in digital photography that some people worry about.

Benji

First of all this was a correction your obviously misleading post that UV is absorbed by a modifier and does cause color cast. Even though this time your statement is much less polite it still makes even less sense.

1. Fluorescent light is not proportional to the UV light that causes it. Secondly UV light is not proportional to the strobe power setting.
So as you change the power of the strobe the ratio of the flourecent and flashtube light changes. One would need to shoot a grey card every time he changes the power, which is not always possible.

2. What if one uses two modifiers made from different materials ? ( I do in 90% cases ). Then two lights produce two different colors that is impossible to fix during posprocessing.

3.And lastly do you have an idea why people pay $300+ for a Chimera sofbox when they could buy some cheap stuff ?

The coating of the coated AB tubes is noticeably yellow--at least it's noticeable if you have an uncoated tube to compare it to.

There is an immense supply of fabric being used for umbrellas and diffusers from China that have UV brighteners. These will floresce blue when used with uncoated tubes. The non-brightened fabric is okay with uncoated tubes.

There is no way to tell visually whether a Chinese product is using the brightened or unbrightened fabric--not even among the products from a given importer. The inability of most Chinese manufacturers to control the specifications of their supply chains is one of the huge problems of dealing with them. We see the same problem in other products, such as foods and drywall.

vadim_c wrote in post #8331258
First of all this was a correction your obviously misleading post that UV is absorbed by a modifier and does cause color cast. Even though this time your statement is much less polite it still makes even less sense.

1. Fluorescent light is not proportional to the UV light that causes it. Secondly UV light is not proportional to the strobe power setting.
So as you change the power of the strobe the ratio of the flourecent and flashtube light changes. One would need to shoot a grey card every time he changes the power, which is not always possible.

2. What if one uses two modifiers made from different materials ? ( I do in 90% cases ). Then two lights produce two different colors that is impossible to fix during posprocessing.

3.And lastly do you have an idea why people pay $300+ for a Chimera sofbox when they could buy some cheap stuff ?

1. My flash units are not fluorescent, they are Zenon gas filled and if there is any change in the color when adjusting the power I have not noticed it in the last 150,000 exposures I have made since going digital.

2. I seldom change modifiers in mid stream and if I do I have a chart that I update monthly with the correct color tempertaure and tint so I don't have to shoot a gray card.

3. Good question. I buy on ebay. and shoot gray cards at the beginning of each session.

Benji

Benji wrote in post #8331743
1. My flash units are not fluorescent, they are Zenon gas filled and if there is any change in the color when adjusting the power I have not noticed it in the last 150,000 exposures I have made since going digital.

2. I seldom change modifiers in mid stream and if I do I have a chart that I update monthly with the correct color tempertaure and tint so I don't have to shoot a gray card.

3. Good question. I buy on ebay. and shoot gray cards at the beginning of each session.

Benji

I just noticed fluorescent! And I also shoot with a WhiBal before all my sessions. I think the pink cast is from the way the camera interprets the light and has nothing to do with the flash bulbs.

If you have non-UV flash tubes (let's put aside the issue of fluorescent tubes, this just confused the issue!), emitted UV from the flashtube will make any cloth with UV brighteners fluoresce as described in RDKirk's post. If you send that UV light to a subject with brightened clothes, or to textiles for a catalog, the flourescence of the subject will render inaccurate all color rendition in the fluorescing object. If you send the UV light to a light box made of material with brighteners, it will fluoresce and throw off the balance of the entire subject, not just causing the clothing/textile to fluoresce, since it is the illuminating source (which is off balance by its own fluorescing!).

Since I never have used any flashtube without UV filtration, I don't know if you bounce a non-filtered tube against a softbox with non-brightened material, will the resulting light at the subject still have any UV content to contaminate the shot, or would it all be 'absorbed' as contended by Benji.