Streaky Lighting

[DesireeM]

Can anyone suggest might be the cause and solution to the streaky lighting on this backlit box?
The cabinet itself is 6" deep and came empty. We installed the guts, including the fluorescent bulbs you can clearly see.

The graphic is printed 15oz flex face material.

Our shop foreman quit a couple months ago and one of the shop workers was promoted to his position.
We've had this streaking issue with another sign since then. I don't know enough about proper depth, spacing, bulb strength (is that even a thing?) to try and solve the issue. Apparently neither does anyone else here...

The other sign that had this issue was 4" deep with white acrylic face and LED lighting so it were a bit different...

 

[J Hill Designs]

I also see 1 Daylight lamp mixed with the cool white =)

lamps too close to the face

 

[Gino]

First of all, not all your lamps are alike in there. You have some cool and day light mixed up.

The lamps are too close to the face. That's commonly called 'Hot Spots'. The back of the face should be at least 4" or more from the most outer portion of the lamp. The more you go, the better the lighting becomes because of reflection. In a 6" can, you should have them about an inch away from the back wall.

 

[Billct2]

Lamps too close to face

 

[DesireeM]

Simple as that eh? just too close to the face?

Yeah the 1 daylight lamp is a whole other WTF issue in itself...Not to badmouth the shop crew but some days I wonder how some of them survived this long. The screw-up stories could fill a bookshelf.

Off topic but for instance: a few years ago the crew had a ladder inside a deep hole they'd dug with a backhoe. At the end of the job they were too lazy to get the ladder out from the hole so they BACK-FILLED THE HOLE AND BURIED THE LADDER and moved on!

It wasn't until we did an inventory that management realized the ladder was gone and inquired about it. Eventually getting the truth from one of them.

 

[J Hill Designs]

The only thing relatively close to that that I have done, was left a walkie talkie up in a 110' high sign - I wasn't about to go get it

 

[Gino]

Yeah, mine's not as interesting either, but we lost a worker on a job site one time. So we left...... thought he was re-locating or something. It was two states away. He turned up a few weeks later. He looked a little more tanned than usual, but we put him to work and he was back to normal in no time.

 

[DesireeM]

Yeah, mine's not as interesting either, but we lost a worker on a job site one time. So we left...... thought he was re-locating or something. It was two states away. He turned up a few weeks later. He looked a little more tanned than usual, but we put him to work and he was back to normal in no time.

I'm sorry I can't tell if you're joking. Please let this be true!

 

[Gino]

Okay, than it's true.

 

[Tony McD]

A pan face would probably make a big difference.
I think they make a diffuser film you could suspend between the light and face to spread the light.

 

[rpffpr]

Can anyone suggest might be the cause and solution to the streaky lighting on this backlit box?
The cabinet itself is 6" deep and came empty. We installed the guts, including the fluorescent bulbs you can clearly see.

The graphic is printed 15oz flex face material.

Our shop foreman quit a couple months ago and one of the shop workers was promoted to his position.
We've had this streaking issue with another sign since then. I don't know enough about proper depth, spacing, bulb strength (is that even a thing?) to try and solve the issue. Apparently neither does anyone else here...

The other sign that had this issue was 4" deep with white acrylic face and LED lighting so it were a bit different...

Those are hotspots. Due to the cabinet not having enough depth. I believe you can put a diffuser on the back side of the acrylic..but you're using flexface.. not sure what you can do to help this besides make the cabinet depth wider.. ive always tried to stick between 8-12" deep when using florescent lamps. You can get away with 6" cabinet/can when using LED lighting

 

[2B]

First of all, not all your lamps are alike in there. You have some cool and day light mixed up.

The lamps are too close to the face. That's commonly called 'Hot Spots'. The back of the face should be at least 4" or more from the most outer portion of the lamp. The more you go, the better the lighting becomes because of reflection. In a 6" can, you should have them about an inch away from the back wall.

+1

 

[Z SIGNS]

Pass this on to your forman

Lamp spacing 101

lamps have to b at least 4.5" from the face

spacing between lamps........double the distance between the face and the lamp.

 

[DesireeM]

Thank you everyone for the tips and information. I'll be ensuring the standards get applied from now on.

We will probably be converting it to LED lighting in which case we may just do perimeter lighting.

 

[2B]

Thank you everyone for the tips and information. I'll be ensuring the standards get applied from now on.

We will probably be converting it to LED lighting in which case we may just do perimeter lighting.

Even if you switch to LED you will still have to have illumination through out the cabinet,

 

[DesireeM]

Even if you switch to LED you will still have to have illumination through out the cabinet,

Yes, that is kind of obvious. I'm probably using the wrong term to describe what I mean.

The box is the same size and style as several others on site. When we got the order the customer informed us that they needed another flex face sign cabinet in the same style as their others. They supplied the specs since they are fairly far away and didn't want to pay for us to come and inspect their other signs to match them. They were certain the current boxes were fluorescent. When we finally got there to do the install we saw that they got everything right except the lighting type. The other signs are perimeter lit LED(or whatever word means that there are LED'S inside the cabinet along all 4 edges facing towards the middle of the sign).

So I don't need to guess. I already know that it will be well lit throughout.

 

[Gino]

Judging by your first post, that box is about 5' x 5'. It has quite a few fluorescents in it. If you only put LEDs around the perimeter of the cabinet, no light will reach the middle. You'll need row after row of LEDs in there to keep it consistent. In small channel letters like 24" tall we still put them like every 3 inches for even lighting.

Unless there is a language barrier, what you're describing will not work. At least not under normal circumstances.

 

[DesireeM]

Judging by your first post, that box is about 5' x 5'. It has quite a few fluorescents in it. If you only put LEDs around the perimeter of the cabinet, no light will reach the middle. You'll need row after row of LEDs in there to keep it consistent. In small channel letters like 24" tall we still put them like every 3 inches for even lighting.

Unless there is a language barrier, what you're describing will not work. At least not under normal circumstances.

There are larger high-output LED's specifically made for the purpose I'm describing. Here's one from Grimco.http://www.grimco.com/Products.aspx?cid=5113&pid=80017

Our sales rep came and did a demo for Hanley and had a smaller cabinet with the edge lighting installed. I haven't seen it used in a larger cabinet but the specifications say it will work up to 6'x6' and our box is just shy of that.

I'm not saying this is what we'll do. It's just an option at this point.

 

[Gino]

See..... ya learn something everyday. Bet they're salty, huh ??

I'm gonna hafta look into those little critters.

I guess they would work in say a 3' x 10' box, too.

​

 

[Westcoast Sign Guy]

I thought I would throw in my two cents about cabinet lighting.

If you want a premium light source and not something Chinese, then we have a high powered LED that's used for both large channel letters and cabinet lighting. The Diodes are Nichia of Japan, who are well known for their superior phosphors that make a bright white, the LED modules are manufactured here in the states .

Their $2.00 each or $4.00 a foot, they have the same approximate light output as a 13mm Tri-Phosphor neon lamp running at 60ma, or a T8 lamp. We've had the Axiom LEDs running in our tests since 2008, and their light degradation is the same as a Tri-phosphor neon lamp.

The light output is incredible and you'll never use anything else after you've tried it!