Bad cold light lamp?

[d.s.]

I recieved today, a replacement lamp for an old zone VI cold light head for my D2 enlarger. The lamp is a V-54 High Intensity from Aristo Grid. It came mounted on cardboard and as I was looking it over I noticed that there is a "weld" in the glass where I guess they ran out of tube and joined the next legnth of tube, and continued making the lamp.

The thing is the glass is clear for about a 1/4 inch where the joint is. No interior frosting, or Phospher in this area. The joint is not on but near the outside edge of the cold light diameter. Wouldn't this "Blank" area affect the light in color or brightness? I thought these lamps were one continus legnth of tube for consistant output and color? Will this make a "hot spot" or "dead" spot? Is it a leak waiting to happen? Should I send it back for replacement?

[Tom Westbrook]

I have a D2-HI lamp and it has a small approx. 1/8" break toward one side, but it's never made any difference that I could tell. Install it and turn it on and see if lighting is even. If memory serves, there will be no illumination where there is no coating, as the coating is what glows--others will correct me if I'm wrong there. Being so small it's doubtfull it will have any effect.

Happy printing!

[David G. Gagnon]

I noticed this on my old lamp, as well as the replacement V54 lamp. The amount of tubing required to make one of these grids is considerable; more for mine as it's for the 1212 head, for an 8x10 enlarger. I have not noticed any irregularities. Besides, if there were, the light being bounced around inside the housing and then hitting the diffusion panel should even out just about anything like this.

If you still question it, Aristo is very helpful, and would be glad to answer your question. They're great people to deal with.

Happy Holidays!

D.G.