A dark topic - Page 1
Forum section: electronics / general

author: TerraHertz
author_rank: Super Contributor
timestamp: February 17, 2016, 10:09:13 am
content: Not electronics, but kinda funny. I'm looking for some plain black velvet fabric, for use as a background for photography and scanning in general, but right now need a few square inches of it to line a camera to microscope adapter tube, to cut down on internal reflections. Had a wasted drive this afternoon to Lincraft, who turned out to be out of stock of black velvet. Should have phoned...So I googled black velvet fabric images. Ha ha... try it. I think this is pretty funny.Btw, who knew there could be so many lens mounting adapters? For examplehttp://www.aliexpress.com/store/group/Adapters-Mounts-Tubes/924907_502570153.html

author: Halcyon
author_rank: Unknown
timestamp: February 17, 2016, 10:12:59 am
content: Take a drive to Cabramatta. Apart from amazing Vietnamese pork rolls, there are a bunch of fabric stores there. You'll want to go early though, car parking is scarce after about 0900hrs. Otherwise you can train it.

author: Artlav
author_rank: Frequent Contributor
timestamp: February 17, 2016, 10:18:17 am
content: For the microscope, what about buying (or printing ( or plagiarizing )) a copy of this painting:https://en.wikipedia.org/wiki/Black_Square_%28painting%29?

author: chefkoch84
author_rank: Contributor
timestamp: February 17, 2016, 10:22:41 am
content: This would be perfect for your application:http://www.thorlabs.de/thorproduct.cfm?partnumber=BFP1Sadly it's not realy cheap.

author: TerraHertz
author_rank: Super Contributor
timestamp: February 17, 2016, 10:28:49 am
content: Quote from: Halcyon on February 17, 2016, 10:12:59 amHeh. Yes, I know Cabramatta well. My ex is Cambodian. And I have spent some time in those very fabric shops. Even bought cloth there myself.But after today's timewaste, I think I'll try at stores I can phone beforehand.Quote from: chefkoch84 on February 17, 2016, 10:22:41 amDarn it, yes it would. So would the black masking tape. This is good to know:http://www.thorlabs.de/newgrouppage9.cfm?objectgroup_id=190&pn=BFP1Maybe next time.I wonder when someone will market Vantablack fabric?

author: AndyC_772
author_rank: Super Contributor
timestamp: February 17, 2016, 10:31:47 am
content: Try these guys; they do all kinds of adapters and oddball photographic accessories, and they ship internationally:http://www.speedgraphic.co.uk/

author: hayatepilot
author_rank: Frequent Contributor
timestamp: February 17, 2016, 10:58:08 am
content: The Fidelio black velvet fromhttp://www.seymourav.com/store.asp']Seymour AV is probably the darkest and best velvet one can buy.The manufacturer of this velvet is JB Martin.This stuf is unbelievably black.Greetings

author: TerraHertz
author_rank: Super Contributor
timestamp: February 17, 2016, 12:32:43 pm
content: Hmm, this thread was meant to be a joke-post, but it's turning out very informative.Quote from: hayatepilot on February 17, 2016, 10:58:08 amSo, white cat hairs should show up on it fairly well?Thanks for that. I've requested a sample (via my US reshipper.)

author: Brumby
author_rank: Unknown
timestamp: February 17, 2016, 03:20:50 pm
content: Have you tried Spotlight?http://www.spotlightstores.com/

author: TerraHertz
author_rank: Super Contributor
timestamp: February 18, 2016, 02:38:48 am
content: Quote from: Brumby on February 17, 2016, 03:20:50 pmYes, that's where I'm going this afternoon. The morning was taken up with a doctor appointment and related stuff.There used to be a Spotlight store in Bankstown, but it closed.Seymourav are very kindly sending me a sample of their Fidelio black velvet. But that will take forever to get here.

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 18, 2016, 03:06:16 am
content: Amateur telescope makers (yes you can make a telescope at home) don't use velvet but a slightly different technique.They paint the inside of the tube black and while the paint is still wet they put some wood sanding dust and shake. The dust sticks to the paint and forms a rough surface. This is then left to dry and then another layer of paint is sprayed to coat the rough surface. Apparently it works wonders for them.

author: Brumby
author_rank: Unknown
timestamp: February 18, 2016, 04:52:02 am
content: Quote from: HAL-42b on February 18, 2016, 03:06:16 amI can see that working brilliantly! - Just don't be too heavy handed with the second coat of paint.I'm going to remember that one.

author: TerraHertz
author_rank: Super Contributor
timestamp: February 18, 2016, 05:57:07 am
content: Quote from: HAL-42b on February 18, 2016, 03:06:16 amThat's a good idea! Only the tube I need to line this time is quite small - fits inside a microscope 23mm tube. Also, I wanted some velvet for use as a photo-background.Anyway... The two Spotlight stores in reasonable driving distance (Auburn & Kogarah) are both out of stock, and it seems their warehouse is too. So, Cabramatta it was. Of course the first one I tried of the many fabric shops had plenty. Trust the Vietnamese to have their shit together. Cotton velvet. $15/meter.Probably not as light absorbent as that Fidelio black will be. But good enough for now. Also, sugar cane iced drinks are delicious.They really should change the name of that street. "John St" seems so incongruous.The *instant* I laid this stuff out on the desk, it starts accumulating cat hairs.

author: TerraHertz
author_rank: Super Contributor
timestamp: February 21, 2016, 02:30:35 am
content: Just an update. The reflection problem is fixed, but not the way I expected. Thanks to HAL-42b for the paint and sawdust idea, it works very well.http://everist.org/NobLog/20151112_planning_vacuum.htm#refl(It's a rather long page with lots of thumbnail pics. This update is down at the bottom. Patience.)

author: HAL-42b
author_rank: Frequent Contributor
timestamp: February 21, 2016, 03:07:00 am
content: I'm so glad it worked!Btw, that clean workshop with the vacuum chamber in the background looks oddly familiar! I may have stumbled on your site while looking for high vacuum measurement stuff. Small world.

author: krivx
author_rank: Frequent Contributor
timestamp: February 23, 2016, 11:38:45 am
content: Quote from: chefkoch84 on February 17, 2016, 10:22:41 amI can confirm from experience that this stuff makes excellent false moustaches.

author: george graves
author_rank: Super Contributor
timestamp: February 23, 2016, 12:27:55 pm
content: Link-bait title!

author: chefkoch84
author_rank: Contributor
timestamp: March 07, 2016, 05:42:54 pm
content: Hey all,Since I just saw the example photo...Another nice thing to get rid of (specular) reflections is to use cross-polarization.Basically you a linear polarizer between light source and object and camera and object and rotate one until the specular reflected illumination is blocked. You will lose at least 25% of the light, so this is just useful when you can afford longer exposure times.You could probably salvage an old LCD screen or crappy 3D glasses for this.I found a nice link here:http://www.diyphotography.net/getting-started-with-cross-polarized-light/Greetings

author: TerraHertz
author_rank: Super Contributor
timestamp: March 09, 2016, 09:00:12 am
content: Relevant (except you can't buy it):Blacker than original Vantablack!Surrey NanoSystems