Blue Light Transilluminator: The Complete Guide

Too many options! Choosing a blue transilluminator is hard. I wrote this guide to help scientists understand why so many labs are switching to blue transilluminators.

Getting Started
My first transilluminator was a UV transilluminator. Our lab bought it used on eBay. We imaged a lot of gels with that transilluminator...

But it sure was a pain to use! If I used the UV light for more than about 30 seconds, DNA damage would wreak havoc on my clones. In between looking at my bands and cutting them out, 30 seconds is not much time! I’m sure you’ve had experiences like this.

The Blue Transilluminator
So I got pretty excited when I first heard about blue transilluminators. There’s no UV DNA damage since they use blue light around 470 nm wavelength instead of UV light at 300 to 400 nm. I spent 2 months studying the many different transilluminator models. I also researched the new blue light DNA stains like SYBRsafe, GelGreen, and GRSafe that could replace Ethidium Bromide.

But I wasn’t happy with the blue transilluminators I found. They were expensive and bulky. So I designed my own. I’ve sold it as the Pearl Blue Transilluminator to scientists all over the world since 2009.

Why I Wrote This
I’ve answered lots of questions along the way. Scientists hesitate to switch because they’ve used UV + Ethidium Bromide their entire career. This guide answers the common questions and concerns about switching to a blue transilluminator. I’ve also included a comparison of the top blue transilluminator models including Life Technology’s Safe Imager 2.0. I believe every lab should ditch their UV transilluminators and Ethidium Bromide for the sake of safety, efficiency, and easy of use.

The 3 Reasons Labs Are Switching
Imagine if your cloning efficiency doubled or quadrupled. Or you could get rid of your lab’s “Ethidium Bromide” station?

Get Tons of Colonies
UV light damages DNA. If you’re doing cloning, you know that your DNA can take about 30 seconds of UV illumination before it starts to result in less colonies. A blue transilluminator uses blue light at around 470 nm wavelength, instead of UV transilluminators which use light with around a 300 nm wavelength. That difference means more colonies. And there’s no hassle, you can image your gels as long as you need to, leave the transilluminator on for a minute, 10 minutes, go get your colleague and bring them back to show them the gel and there’s still no DNA damage.

Make Your Lab A Safe Place
With a blue light transilluminator you can leave behind Ethidium Bromide and UV light.

Goodbye Ethidium Bromide: Ethidium Bromide requires special handling and disposal. Blue light dyes like SYBR Safe are a safe alternative to Ethidium Bromide. Throw away gels stained with blue light dyes in your normal lab trash, and your electrophoresis buffer can go down the sink. Here’s a study on the safety of SYBR Safe. However, some blue light dyes like SYBR Green are hazardous, so read the protocol before buying. (As an aside, many labs used Ethidium Bromide with a blue transilluminator. It works well, though EtBr bands aren’t as bright as with UV.)

Hazards of UV Light: UV light harms your skin and eyes. Universities and companies published warning guides to help their staff avoid skin and eye damage. Here’s an example from the the University of Washington “Hazards of Ultraviolet Light”.

Free Up a Lab Bench
Does your lab have a separate bench designated the “Ethidium Bromide Station”? It probably has a separate gel box, pipettes, tips, gloves, and special disposal. All to make sure nothing else gets contaminated. A blue transilluminator with a safe dye like SYBR safe means there’s no hazardous chemicals. Reclaim that extra lab bench for something better... like your lab’s new awesome sound system ;)

The 4 Biggest Concerns
1. Are blue transilluminators expensive?
Blue transilluminators cost between $300 and $1,300. I’ve got a price comparison below for the most popular transilluminators. While Ethidium Bromide is super cheap, the blue light dyes are a bit more expensive so make sure to take that into consideration.

2. Will my bands be as bright as Ethidium Bromide?
That depends on the blue light dye that you choose. You should expect your bands to be as bright as Ethidium Bromide. That said, some labs do keep their Ethidium Bromide around specifically for extra-bright publication-worthy gel photos.

3. Do I have to change my protocol? Do I have to post stain my gel after?
There are no changes to your protocol. Mix the blue light dye into your gel before pouring. Keep your same loading dye, ladders, and running buffer. A post stain is an option for blue light dyes, but not required (most labs don’t).

4. Can I still use Ethidium Bromide?
Yes, Ethidium Bromide works with a blue transilluminator. Because there’s no UV DNA damage, you get more colonies. But if you do feel like switching to a blue light dye, there are great options available.

Choose the Right DNA Stain
There are many different DNA stains. Many companies show comparisons about how their stain is the brightest! They can’t all be right, so how do you choose?

Play It Safe
Buying a new piece of equipment is stressful. You’ve got enough to worry about just getting your experiments to work. And to add on top of that picking out a new DNA stain too? Well, you can start by eliminating one variable, the DNA stain. Start out with SYBR Safe. SYBR Safe was one of the first blue light dyes on the market. It’s manufactured by Life Technologies (previously Invitrogen). It does a great job with most samples and is sensitive down to to 500 picograms of DNA. Plus, I can offer you a free sample of SYBR Safe DNA dye to try out in your lab. Check it out here:

Go Pro
That said, there’s a lot of benefit from picking the right dye for your needs. For instance, check out SYBR Gold if you need really high sensitivity (25 picograms of DNA). If your lab is on a tight budget, experiment with lower cost dyes like GRSafe or Gel Green.

Choose the Right Blue Transilluminator
Want to get the right tool, without getting ripped off? Here’s 3 things to look out for!

Blue Transilluminators range from $80 (for a DIY kit) up to $1,333 for Life Technology’s Safe Imager 2.0. You can save about $1,000 on a blue transilluminator by doing your homework (reading this guide is a great step!). If you’re really scraping, check out lab equipment auctions on

You’ll want to get a transilluminator that can fit your gels. There are roughly 2 general sizes for transilluminators. (While designing the Pearl Blue Transilluminator I found that 90% of labs use gels smaller than 10 cm square, or about 4 inches square.)

Regular: fits gels up to 4” square. This includes gels like the popular Owl B2 (14 x 12 cm), Owl EasyCast B1 (11 x 9 cm), Owl EasyCast B1A (8 x 7 cm), Owl A2 (8 x 7 cm), Owl C2-S (7.5 x 5 cm), Owl D2 (14.4 x 10.2 cm), Carolina NG (8.25 x 8.9 cm), BioRad Mini-Sub Cell GT (7 x 7 cm)

Big: Gels larger than 11 cm square (4” square), for instance if you run 20 samples on every gel. The Owl A1 (25 cm x 13 cm), Owl A2 (25 x 20 cm), Owl A3 (40 x 23 cm), Owl A5 (25 x 20 cm), Owl A6 (25 x 23 cm) are a few examples.

Check the warranty policy. Most transilluminators use Blue LEDs which should last for over 5 years, but a clear warranty is helpful in case anything goes wrong.

Return Policy
Switching to a new transilluminator can be stressful, and you might even decide you want to return it and get a different one. Most companies don’t have a clear policy, a few have a 30 day policy. I found that it takes about 3 months to properly test a new blue transilluminator (it might sit boxed up for 30 days before you even have time open it). That’s why Pearl Blue Transilluminator has the longest return policy in the industry. 90 days, no questions asked.

Outside the United States
Make sure the transilluminator will work with an international power adapter for your electrical system. Blue transilluminators are low voltage and should have no problem, but expect to buy a pin-adapter.