How to take fluorescent pictures

Slow decay


One of the most recurrent jobs I’m asked to do as a scientific photographer is fluorescence photography. This is so because fluorescent compounds are usually very eye catching and offer a good picture to illustrate your work. Even, sometimes, the picture itself might have scientific importance. Sometimes the picture depicts different compounds where you want to show the difference in colors or intensities. Other times there is a change and you want to display it, like in the image above, where the sequence shows how the diffusion of ambient oxygen into the solution makes the luminescence turn noticeably off (which means you can see the “invisible” oxygen flowing and mixing into the liquid – the one on the left is completely oxygen free-).

A few days ago I was asked (one more time) how these pictures are taken. For the professionals on low light photography it’s rather simple, but for many amateurs taking pictures in darkness or using invisible light seems to be a very confusing concept. The target of this post is to give some advice to novel photographers on how this kind of pictures can be successfully taken.


The scary part made… less scary

  • This kind of photography takes advantage of fluorescence, which is the ability that some chemical compounds have to transform invisible ultraviolet light (usually UVA, sometimes UVB) into visible light. The net effect is that the compound seems to glow in the dark. The key concept to remember is: because you are capturing the light emitted by the compound, any other visible light existing in the scene will compete with the one you want to photograph and will reduce the contrast and glow effect. For this reason you must take this kind of pictures in absolute (or almost absolute) darkness. Even a slight amount of “parasite” light can decrease the sensation of glowing. Even if you don’t see it with your eyes, the camera is especially sensitive to the parasite light, as it will probably be a long exposure picture.
  • Remove any other fluorescent object from the scene. If you are trying to take a picture of something that emits light under ultraviolet radiation, any other object emitting light in the same circumstances will interfere with the picture. This might sound obvious, but sometimes it is not. One mistake I’ve seen many amateurs to make is using a white paper as a base, to put the subject above. It might seem to be a good way to get a clean background t turns out that most papers will glow white under ultraviolet light (so they look whiter under sunlight) and will spoil the result. You can use instead recycled non-bleached paper (as long as it doesn’t glow) or, as I usually prefer, a piece of black cloth. Also, wall paint can be luminescent, or some plastics. The best way to test it taking a picture without the subject: the more light you see, the worse the conditions are.
Fluorescent paper and ink
On the left the text is written using fluorescent pencil over non-fluorescent paper. Only in the full size picture the paper can be slightly seen. On the right a standard A4 paper, glowing in blue. The camera is drawn using a standard pencil (not fluorescent, but can be seen by contrast with the fluorescent paper) and the flash is drawn using the same fluorescent pencil used on the left. The contrast in this case is clearly lower. For both papers the background is a piece of black cloth.
  • A tripod is compulsory. I know cameras nowadays perform really well on high ISO, but still the noise level is important if you go past 1600. Taking into account that your subject is not going to move, using a tripod will allow you to use the lowest sensitivity, take multiple pictures with the exact same composition and focusing precisely, which leads to the next point…
  • Use live view and manual focus. Manual focus may seem a bit from the past, but is very useful in this kind of photography. Once you achieve the focus point in the exact place you want, manual mode will guarantee that the point will remain in focus for the rest of the session. You can take multiple pictures without touching anything, and you won’t need to worry about focusing. Also, the correct focus point is the same under visible light and ultraviolet light (this doesn’t happen in infrared photography), because you are not capturing the ultraviolet light, but the visible light converted by the compound. This means that you can focus with all the lights on and, afterwards, turn them off and use only the black light, instead of doing all the procedure with the black one. For more information on how to focus with precision you can read the post Sharp focus for the sharp eye.
  • Beware the white balance, automatic is not as good as it seems to be. Although the black light is mostly ultraviolet light, it also emits a little amount of violet and blue. This means that the scene will have a blue glow or “haze”. This glow is normal, is part of your light, but the camera doesn’t know that. It believes that this should be neutral grey and will try to compensate, destroying most of the colors. The solution is to accept the blue haze as a part of the picture. I always use automatic white balance (shooting in RAW, of course), so the camera choses the blue/yellow (which is usually wrong) and green/magenta (which is usually correct) balance. Afterwards, when processing the RAW file, I change to “daylight”, and set the green/magenta value to the one calculated by the camera. Finally, if result is not appealing, I slowly modify the blue/yellow balance by hand until it seems natural (which should never destroy the blue part).
  • Regarding the lenses, a wide fast lens will allow shorter exposure times. Although you will be using a tripod, and speed is not limiting, the longer the exposure the more likely to hot spots to appear. Long focal lengths are not advisable, they will yield a very shallow depth of field (which will make focusing and getting sharp images difficult) and you will need more physical space to put everything in frame. The higher focal length I have used is 100mm (on full frame), and only because I could use the macro capabilities of the lens. On the opposite side, a very wide lens will create one out of two problems: it will make our subjects very tiny while it fills the frame with “emptiness”, or it will fill the frame with the subject but deforming size and proportions. Although both cases might have artistic purposes, in scientific photography accuracy is often desired. For those reasons my recommendation is to constrain the focal length to 35-70 mm. 50mm 1.4/1.8 lenses are very common and satisfy both requirements with good sharpness.
  • Finally, about light placement, I usually place light in front of the subject, above the camera, facing the scene (like a hot shoe flash but without touching the camera). As accuracy is desired, the light source should be parallel to the plane of focusing, otherwise some objects will get more ultraviolet light than others, glowing more (the intensity of glowing directly depends on the amount of light received). Placing the light over the camera usually avoids its appearance on the picture (for example, reflecting in glass). If placed behind the scene it must be carefully placed so it doesn’t appear in the frame (it is not only unsightly, as it emits some visible light it will compete with the main subject). Side locations are not recommended if a faithful approach is desired.


OK… I think it’s cool. How can I do that?

Probably, you won’t be a scientist with access to professional ultraviolet lighting or fluorescent compounds, but that doesn’t mean you won’t be allowed to have some fun with it.

Amateur ultraviolet lights are nowadays very cheap, and can be found in almost all lamp shops or internet. If you think about it, if many pubs and clubs have this kind of illumination, there must be a place where they buy it.

I got my ultraviolet fluorescescent lamp on a local shop (in a small city) for around 20 euros (22.50 USD) a few years ago. It included not only the lamp itself, but also the ballast, starter and 2 meter wire to plug it. Taking into account the amount of light it can provide (similar to a typical fluorescent lamp, but in the ultraviolet range) I think it’s quite cheap. It has been in service sporadically for 14 years, and still working.

On the other side, you can get hand lamps based on ultraviolet LEDs on internet with a very low budget. I fond mine on Amazon for about 7 euros (8 USD). The official price was 20 euros too, but it was in one of those sales that last for many many months. The advantage is portability (it works with AA batteries, not plugged), but it’s much less powerful. Which one best suits you is your choice.


UV lamps OFF

UV lamps ON
Top: My fluorescent black light setup and my handheld LED-based UV light. Bottom: Both of them turned ON. Although the fluorescent tube has more intensity, the LED lamp emits more in the visible spectrum (which is bad in this case), so it appears brighter.


About fluorescent substances, there are many ways to get them. Some are natural. For example, chlorophyll, the green pigment in leaves, fluoresces in red. This means that taking the picture with ultraviolet light will render all the green parts deep red. Also, extracting the pigment is easy, just smashing some leaves in alcohol and filtering the liquid afterwards. This way you can isolate it and use it for any other purpose.


This is a standard bush, with green leaves. The picture was taken using only ultraviolet light, so the leaves appear red because the chlorophill in the leaves fluoresce in red. This effect can be achieved in many vegetal species.


Other source of fluorescent pigments is fluorescent paint. Some of them are used to paint on paper (like pencils or markers). If the paper is not fluorescent (many are), you will see the annotations glow while all the rest is dark. This can yield to interesting pictures, for example, a composition of a book with fluorescent annotations. Other paints are made to be used in the skin (e.g. make up). This way you can paint a model and get nice pictures where only a few parts or patterns are seen. As an example you can see the work of John Poppleton.

In general, if you see something that reacts to this kind of light there is a chance of using it for fluorescent photography. Sometimes you can use the item itself as an element in a more complex composition, and sometimes isolated and used in a completely different way. As in many other aspects of art the limit is your imagination.

For another example of this kind of photography you can read my other post The fluor rainbow.


The rise of the phoenix

The rise of the phoenix
The rise of the phoenix explanation

Some people like to find hidden figures in the clouds…
I enjoy doing it on the fire, in a blink that lasts less than a millisecond.


Today’s picture came about as a game. Last Easter I was with some friends doing a barbeque at night and, while we were waiting for the embers to be ready, I started playing with the camera. Fire is usually seen as a continuum, a changing abstract form without a specific shape. But being very bright it also becomes the perfect subject to experiment with very high shutter speeds. So, after increasing the speed time after time, I came to the realization that in many pictures you can get a very nice and specific picture of the of the flames’ shape. And at that moment I started to see familiar figures and stories in the fire, in the same way some people like to see them in the clouds. I became a kind of oracle reading the flames instead of the tea grounds or the crystal ball.

In this picture I caught a phoenix, the mythological bird (I guess in the same way as Pokemon can be caught), being born in the flames. It is shown from the front side, looking directly at the camera with its right eye and the wings raised. This shape only existed for an instant, half of a millisecond, but just the exact instant the shutter of my camera was exposed (lucky me!). And this way, the birth of this mythological creature was captured just to be devoured by the fire one moment afterwards.

Ok… Perhaps you need a little bit of imagination to see it (that’s why I added the explanation image). But I think that not all pictures need to be serious. Sometimes, the key to a good picture is just setting the mind free and play. Experimenting just to see what happens.

Now, I wonder… Does everybody see the phoenix? Does anyone see another thing? Does people see this as amusing as I do, or am I the only weirdo that enjoy this? I have more pictures like this one, with other stories (although not as clear as this one). I guess someday I might release another one.

May the fire be with you… and your steak (vegetarian? try calçots).

What should not be

What should not be

Something I have learnt the hard way in the last few months: Never give yourself 100% to another person if that person needs help. If you do, the other person will soon start to want more and more help from yourself. Being at 100% from the beginning won’t allow you to give more and, in that moment, s/he will reproach you that instead of thanking for everything else you did (even if you did a lot expecting nothing in return, just for free). Instead of that just involve yourself as little as possible and nothing more. They will thank you exactly the same as if you had gone 100%, and when they ask you for more it will be easy to give just a tiny bit more to keep them happy.

On the long run, it doesn’t matter how much you did, just the last step matters. It’s a really sad truth, but it’s the way most people act.

Nothing matters except how much you can satisfy the expectations they have built about you (their expectations, created in the fantasy world of their minds). You effort or ability to be able to reach those expectations, even partially, are not important. If you are not able to reach the “final line” it doesn’t matter how much you helped or how hard you had to work to help. If you don’t give everything they expect to you, they will treat you as if you had given nothing at all.

In films effort is always rewarded and doing the right thing is worth at the end. I guess that’s why films exist: they comfort us and offer a different outcome to that of real life. Instead of a tug of war where everybody tries to get as much as possible from us giving as less as possible, they show us a fair ending where karma exist and everyone gets what they deserve. But in real life effort usually doesn’t compensate and look and luck are the only forces moving around.

At the end, we all carry the “evil” within us, even when we consider ourselves in the “good team”. If you look at yourself and think you are a good person, probably you are just looking towards the side that suits you.



“Fear is only as deep as the mind allows”. Japanese proverb.


So, this is how my little journey into my mind ends. Perhaps it wasn’t deep enough to be memorable. Perhaps it wasn’t long enough to be taken seriously. But if you take some time to think on each text, to see each picture, to see the whole picture filling the gaps in every text, and also between texts, you will find some richness that sometimes we forget.

It was a lovely journey through a beautiful land. And it was also a lovely journey to my mind, to my thoughts in the last few months. Some thoughts that we don’t consider important until a bad moment arise, in the same way that we don’t stop to think about the air and breathing until we discover, usually panicking, that we cannot breathe.

This is my tiny contribution for a journey that, sadly, every human being has to do in their lives from time to time (sometimes even more than once). I hope that you have enjoyed it and it helped you to understand, comprehend and see the beauty in a situation usually considered as ugly and unpleasant. Or at least to understand better the people who are passing through a time of suffering.

Even in the worst situations we can find something beautiful. Even in the worst situations we can learn and get something good from them. Usually we are not able to change the bad things, not even help the ones suffering around us (or ourselves). But, if we have to go all the way through it, at least let’s get some profit from it. If we cannot avoid it, at least make it worth.

We can always end a day a little bit wiser than we started it.

Mirage II

Untitled-1Mirage II

“I spoke about wings, you just flew. I wondered I guessed and I tried, you just knew. I sighted, but you swooned”. The whole of the moon – The Waterboys.


If we accept the idea that we are our personalities, that we are the software running in our brains, my favorite question is: How many “me” exist?

We can start assuming that there is only one: the one I know and dictate the way I act every day.

But when we talk to people (or even if they “know” us without talking) they also get the idea of “ourselves” into their brain, into their memory.

But that “me” that inhabits into their minds is incomplete by definition. Only I can see my true self (and not even always you can be completely aware of the whole of it). The rest of the people are forming an image of the person who you are based on incomplete information (and sometimes even wrong information). They are building a copy of your personality in their minds that is, almost for sure, different from the one you really are. And afterwards, when people try to analyze any situation trough that personality (e.g. trying to infer what you mean from something that you say), those differences would probably lead to different interpretations. We might believe that we are funny just because we know everything we say is a joke, and still be considered stupid or grouchy by others. And for those people that other personality is as real as our own to ourselves.

Seen this way there is not just one copy of what we call ourselves. Every person who knows us, every family member, friend, acquaintance or even a random person who we met briefly, has their own and personalized copy of ourselves. A different “person”, created using an incomplete pattern, based on the real one we are.

But, when we disappear, when we die and our corpses rot… Can we really say that we are gone as long as there are other copies of ourselves populating other minds? Are Napoleon and Elvis gone if we still know who they are, how they thought? In that way, our personality is a kind of life that spreads like a virus. It starts as a single specimen, inhabiting an empty brain, and it develops influenced by its environment. But as long as the personality is exposed to other brains, it “infects” them, residing for as long as the memories last. An altered copy of ourselves, in a way like other alive beings mutate. And those new hosts can spread even more that personality to new individuals, breaking the barrier of the individual and converting our personality into a species, where every person will have a different individual belonging to it, as Elvis is different for every one of us, even if we never met him in person.


Place: Sant Vicens de Torelló

Speed: 1/100 s.

Aperture: f/6.0

ISO: 640

Focal: 105 mm

Model: Alba Pe [FB] [IG]

Mirage I

Untitled-1Mirage I

“God have mercy on the man who doubts what he’s sure of”. Brilliant disguise – Bruce Springsteen.


Sometimes I ask myself: who am I? Does my body form part of what I am, as a person? Or does only my mind take part on what I call “myself”? This raises interesting questions about me. For example: If I could design a robot with an empty brain, would I be able to transfer the person I am and keep living on it? Would it be the same being as I am right now, or it would be another copy, someone independent? Would the robot act as myself, or sooner or later would diverge from the actions and thoughts I’d have taken, limited by its own hardware. Is our consciousness limited by the hardware (our brain), or we are just software and the physical part only provides life support but nothing more?

I’ve always defended the thesis that we are only our memories. What you do today, what you think, the person who you really are, is based on the things that we remember from our past. The good and bad experiences formed our personalities. If we change our memories all the erased past would simply disappear and to our perspective it’d be like it has never happened. Even the new memories would seem as real to us as any other memento. I always see this using the metaphor of time travel: If someone just traveled to the past and changed it in a way that a new “alternative future” formed, from our perspective only the alternative timeline would have existed, and we would never know or be aware of the original one. Only the time traveler would know both of them, and changing the timeline many times would be transparent to the rest of its inhabitants. Something similar happens with our memories, we trust them because we know they cannot be changed arbitrarily but, if it was possible, how could we distinguish between the original and real memories and the altered ones?

Even more… Can we say that we would be the same person as we are if we just lost our memories, if only we had the new memories from that moment on and not any other background information? I guess some amnesic people could solve that question for me.

From this perspective, what we are seems quite fragile: Just a piece of information coded chemically in less than 2 kilos of organic matter (and half of it is just water). And if that information is lost: an accident, an illness, or just by chance… Are we lost? Would the result be the appearing of another different person, independently of our DNA? Or we would still be the same person, and our personality and memories don’t mean too much in the process?

I believe that a person is not a body, but a personality. The accumulation of decisions you take and the actions performed. We are our memories and our choices, the way we relate with everyone else and the “algorithm” that decides what we will do, how we reason, in every specific situation.

In the picture: a graffiti painted in the walls of an abandoned building, reflecting in the water of a puddle in an oneiric way. The way the picture is taken and processed distracts the mind for a few seconds while it tries to interpret the reality shown. This is my way of representing the fragility of the mind, and how who we are is extremely dependent of a fragile and voluble organ which does its best to process all the information around us, but not always in the correct way.


Place: Sant Vicens de Torelló

Speed: 1/80 s.

Aperture: f/6.0

ISO: 800

Focal: 105 mm

Multiple personalities

Untitled-1Multiple personalities

“But she crawls under your skin, you’re never quite the same, and now I know she’s got something you just can’t trust”. Invisible touch – Genesis.


It is a clear fact that a smile is one of the purest signs of happiness. A smile shows that everything is all right, that the world around the smiling person is safe. Who wouldn’t love to see their family and friends smile?

But a smile can hide many things. So many people suffering don’t express it publicly. Weakness is a taboo topic in society nowadays, as it has been for all our history. Only the strongest people prosper and get the life of their dreams. The weak ones get consumed in the process until they submit to somebody better. And in this fantasy that society has made we hide ourselves, showing our stronger face like a mask that covers who we really are, never showing our weaknesses so nobody can use them against us.

But what about the action of using the smile to protect the people who care about us? Because sometimes you wear the smile not to avoid getting hurt, but to make other people happy, even if you are not. Pain is not accepted in society. You must always fight against it. It’s unpleasant to see it, to be with someone who is suffering it. So we try to force the suffering person to smile, negating the obvious pain, so we can feel good near him or her. Even if that is the least thing that the suffering person needs.

You end looking at someone and not seeing the real human being behind, just the mask. And the borders of the mask fade, mixing with reality, not knowing anymore what is the real person and what is just the tale invented to keep the normality in their bounds.

So, next time you see an estranger smiling stop for a second and think: Is s/he really happy? Does it look like a sincere smile? Or it is just another mask, covering a harsh mountain of problems, deceptions, pain and suffering this person is suffering in its inside?

And… what about the next time you see a close friend smiling?

In a perfect world, a smile should never have to be used as armor against the people who care about you…


Place: Bosc de Can Ginebreda

Speed: 1/125 s.

Aperture: f/4.0

ISO: 100

Focal: 105 mm