EEVblog #1373 - DIY PCB Photograhy LED Light Box - Part 2

Part 2 of the DIY PCB LED light photography box.
This time experimenting with top and bottom side emitters and paper reflectors to give an even better result.

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#LED #DIY

[eagerestwolf]

I’d say the colors are far more accurate on the photo with the paper and LED ring at the top. Also, removing the alfoil may do more harm than good. Having that reflective layer behind the diffusive layer is probably helping to spread the light better.

[kinstar]

White paper actually makes a very good reflector it also helps soften the light more evenly

[eliotmansfield]

blimey it’s UK v OZ lightbox day - clive just released his Tupperware one!

[kjellno]

It looks to me as the picture with the LED's on top with paper gives a better depth in the picture. Look at the connectors to the right. The surface is not washed out as much as the other picture. Otherwise there's no differense in my opinion.

[dcallan]

black velvet works good or lift the board up a couple of inches makes the background fade a bit

[petersage]

Reminds me of a MythBusters episode about using mirrors to get sunlight into a tomb. The results were borderline plausible until Jamie stepped into the beam with his iconic white shirt.

[djvanzz]

Take apart an lcd screen, and you can get a nice flat bright diffused light source!

[TheDefpom]

@16:30 the left image has better contrast making it easier to see the traces, again, alfoil wins.

[alflud]

The reason you got increased lux with the paper is because the paper is diffusing the light as well as reflecting it. You should look into using a diffuser from an old tv - it'll do a much better job at spreading out the light evenly than the paper does.

[killymxi]

The last one (with the LEDs raised) looked the best. Best colors, and metal surfaces actually look like metal.

[dr.lexwinter]

You might be interested in using matt white paint - instead of alfoil. Besides professional reflective materials for grow boxes flat white has a pretty high RI, better than silver gloss, or metallic tapes and foils by far. It's so weird to see in action, too, at first thought it's counter intuitive because it's not 'reflective' looking in appearance.

[johnkortink]

For many years I've been using a frame draped with thin white curtain material, hole on top, white paper below item, lit from the outside by building site lamps (incandescent or recently 5000K LEDs). Works great. Main ingredients (as sort of discovered in this video) : natural light, plenty of it, and diffuse diffuse diffuse (and maybe diffuse some more). Bon appetit.

[tad]

Most copy paper contains UV brighteners. If the LEDs are bleeding any UV, some of the light increase could be from the UV being fluoresced back.

[rwbishop]

Like an old time 'copy stand' I'd try to get the subject illuminated from a 45° angle all around to mitigate glare... use a 18% grey background, and ditch the auto exposure for a histogram & exposure bracketing. All while focusing manually... it's basically a macro shot.

[lambda]

One of the earliest professional YouTuber gluing LEDs salvaged from light bulb and Alfoil in a cardboard box to get better ligting

[Spikejwh]

Well, some 20-30 years ago I made a box with 2 UV fluorescent tubes on the bottom and 2 tubes at the top.
In the middle is a drawer with a glass bottom.

I print both sides of PCB on clear overhead projector sheets and make an envelope with double sided UV sensitive PCB in between.
Put envelope + PCB on glass bottom of drawer with another glass plate on top and slide the drawer in the box
Light on for 300 seconds.
Develop in drain-cleaner solution (30 grams drain cleaner in 1 liter of water)
Etch in Iron chloride.
Drill by hand or with a CNC machine.
-
Works perfect and very simple.

The light is not that critical... as long as there is enough and *it is Ultra violet!*

Tip: I made a timer for the lights with 3 thumb wheels to set the time in seconds.
You do not need that, I always use 300 sec.
So a fixed 300 sec timer without fancy thumb wheels will work fine.
Timing is not very critical, just experiment a bit.
The used light tubes will have an effect on the timing.

[Correalian]

LED ring at the top looked nice and sharp with the text on the chips a bit clearer and the colours looked a bit better too but they all still looked really good.

[rudgespeed]

The UV brightening agents in the copy paper are messing with the lux measurements. You can see the purple cast in the video camera. The color temperature can get screwy because of that as well.

[smunaut]

Could the LED emit some UV that get converted by whitening agent of the paper ?

[edwardbowers]

I have an enlarger which uses a polystyrene lined box to diffuse the light before it passes through the film. You could use a polystyrene box like the ones used for shipping fish/meat, or even just reuse some polystyrene packing, then you wouldn't need to line the box or anything.