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Roller Derby Colour

Back when I started using flash to shoot Roller Derby (in an attempt to get sharper blocker shots for GRG bout programme covers) I had huge colour balance problems.

A quick colour 101 for non-photographers. Colour is said to have a temperature, because it’s defined as the colour that would be produced if an ideal black-body radiator is heated to that temperature. Heat a piece of iron to 900 Celsius and it’ll glow red hot. Heat it to 5778 Kelvin (5504 C) and, assuming it hasn’t vaporised, it’ll glow the colour of the sun. 5778 K is really hot. Digital cameras expect daylight to be 6500 K. Confusingly, what we refer to as warmer light (more orange) is produced by cooler temperatures.

So the problem is that usually the hall lights are warmer (more orange) than the flashes, so the closer a skater is to a flash the colder (bluer) the light on her will appear. At worst, skaters close to a flash will be lit with more cold light, and at the same time skaters further from the flash will be lit with more warm light, so it’s impossible to get everything the same colour when editing. As well as making the editing much more complex this annoys me more than a little.

Now I know that most people probably wouldn’t notice as what they’re looking at is the gameplay in the image, but I’m a photographer. We worry about these things. And as anyone who had a good giggle and my reaction to them opening the Berlin Arena skylight in the middle of a game will tell you, I’m kinda picky about colour calibration.

BoutDay GelsThe solution is to add colour correcting gel filters to the flashes, and these are readily available in different strengths – most commonly full CTO (convert to orange), ½ CTO and ¼ CTO. The problem is trying to figure out which filter, or combination of filters is needed for an unfamiliar hall. It’s difficult to eyeball this as your eye tends to compensate for the colour of the ambient light, and after a while you just stop seeing it. Then you look at a correctly balanced image on a camera screen and it looks too blue.

What I needed was a way to measure the colour temperature at a venue so that I don’t have to guess which gel to use, or work it out by trial and error. There are two solutions to this problem:

BoutDay-Passport1. Buy an expensive colour temperature meter (£900).

2. Use an inexpensive grey card and a laptop. A grey card is a carefully manufactured reference sheet that is exactly 17% grey, with no colour cast. If you take a shot of this card lit by the room lights, the camera can automatically apply a colour correction to the shots you take to remove the colour cast.

Once you’ve done this the camera clearly knows what colour the room lights are (measured on the Kelvin scale), but it won’t tell you. Clearly nobody at Canon (or Nikon) thinks that this is useful information. So…

BoutDay Lightroom Card1. Calibrate your filters by taking a series of RAW shots of the grey card, flash lit with each gel and combination of gels that you’re going to use. Pull these into Lightroom and eyedropper them to correct the colour. Note the colour temperature and tint of each.

There doesn’t seem to be a linear relationship between filters and Kelvin value, that is, you can’t use 2 stacked CTO filters and get half the Kelvin value of one filter, so you have to measure all of them. These are the figures I got for my set of CTO gels, both temp and tint (Tint explanation added at the bottom):

Gel Filter Colour Temperature Tint
Bare flash 6750 +6
1/4 CTO 5100 +6
1/2 CTO 4250 +5
1 CTO 3400 +11
1 + 1/4 2950 +12
1 + 1/2 2750 +16
2 x CTO 2350 +9

BoutDay Select2. At the venue shoot the card under the ambient lighting and use that shot to set the camera’s custom white balance.

BoutDay BalanceUse a low ISO as noise seems to make this less accurate. Shoot another general shot of the venue with this custom white balance setting. Again, user RAW as Lightroom won’t give you colour temperature information for a JPG.

BoutDay Temp3. Pull this custom balanced venue shot into Lightroom and look at the colour temperature and tint values. Pick the filter that is closest to these values. Temperature is more important than tint. This filter should correct your flashes for ambient conditions.

BoutDay Colour4. Work out the manual colour balance and tint settings necessary to replicate this measured camera setting and write them down. That way you can just set the balance manually on subsequent visits and don’t need to keep shooting grey card shots (and bringing a laptop with you). Colour space calculations are complex so it’s unlikely that your camera and Lightroom will come up with the same values.

For example, at the Glasgow Arc I measured 4200K +27 in Lightroom, and when I set 4200K +6 magenta in the camera I get 4200K +26 back in Lightroom.

However, I measured 3500K +36 in the Kelvin Hall, but had to set the camera to 3400K +9 magenta to get 3550K +32 back in Lightroom. Close enough.

So for the Arc I use a 1/2 CTO gel (measured at 4250 +5) and for the Kevin Hall I used a full CTO (measured at 3400 +11) and get, for me anyway, an acceptable match.

Or you could just guess and swear at Lightroom a lot later. :)

DaveMc, Feb 2015


BoutDay TintAny incandescent material, like our ideal black-body radiator or red hot chunk of iron, only varies between red and blue as you heat it up. Unfortunately for us there is another axis in this puzzle, between green and magenta. This shows up when dealing with fluorescent and gas discharge lights as a rather unpleasant green cast. You correct for it by adding some magenta. In Lightroom this is a tint value and on a Canon camera it’s a White Balance Shift – positive to add magenta and negative to add green.

Roller Derby Photography

Last year, while I was in Dallas shooting the World Cup, there was some talk of writing something about Roller Derby photography. At that point I didn’t really have the time, but now that I’m loitering around airports a lot waiting for domestic flights, time isn’t as much of an issue. So here goes.

I got involved with Roller Derby in 2010 when my friends Sarah and Jen started skating for the Glasgow Roller Girls (as they were then), and asked me to come along and shoot some bouts. I had never photographed sport of any description before, but I gave it a go and I’ve been shooting Roller Derby ever since. Now, 4 years, 3 World Cups, 160 bouts and 26,000 posted photographs later (more or less), I’m still doing it. So, equipment first.


BoutDay GearFor the most part, camera equipment doesn’t really matter that much. You can take great photographs with a Box Brownie. But in sport photography it really does. Especially when working in poorly lit sports halls trying to get sharp shots of fast moving athletes.

This is the current contents of my camera bag when it’s in Derby mode: 2 camera bodies with vertical grips, 4 lenses, 8 camera batteries (3 in the cameras), 12 memory cards and a belt system to carry it all around.

BoutDay-LenszillaMy main lens is Lenszilla. A Canon 70-200 f/2.8L IS II USM to give him his full title. This is a staple of the Derby photography world, and I bought mine when I signed on to shoot the first World Cup in Toronto with Team Scotland in 2011.

I don’t use him for anything else because he’s just too big and heavy, but he lets in a lot of light, tracks focus on moving subjects really well, and is sharp as a tack and tough as old boots. He’s usually attached to my Canon 5D Mk3.

My Canon 7D with a wide zoom, usually the Canon 24-105 f/4, is on my other hip for general team shots and centre track stuff.

You can certainly shoot with a lot less. You really don’t need 2 cameras and I know several photographers who use only one, but I’m paranoid about equipment failure and have accumulated this stuff over a number of years, so it’s a setup that works for me.


At the World Cup in 2011 I saw that most of the Canadian and American photographers were using off-camera flash to cut through the bad lighting and freeze the action. So with the help and advice of Joe Rollerfan (thanks Joe) I set about assembling mine. It’s been through several upgrades and changes since then, but this is the current iteration:

BoutDay Flash

  • 3 Nissin MG-8000 heavy-duty flashguns (Granite, Bruiser and Fierce);
  • 3 Godox Propac power supplies;
  • A Phottix Odin wireless trigger system;
  • 32 rechargeable AA batteries + a few sets of spares to power the gun electronics and the triggers.

With this system in place I can pretty much ignore the ambient lighting and get consistent results, and they’re on very low power, so the players and refs generally don’t notice them.

Granite sits on a stand at turn 2, Fierce is on a stand at turn 4 and Bruiser is clamped up somewhere near turn 1. All well above eye height. They all point more or less at the Jam Line and are fitted with orange CTO filters to match the ambient lighting. I use them in ETTL mode so they handle their own power levels for different skater distances, and the Phottix trigger let’s me control them remotely and turn them off when they are in my line of sight. It’s not a perfect system and can be confused by flickery hall lighting, but most of the time it’s close enough.


My main objective is to document the event without getting in the way. Preferably without being seen. I know some leagues use high-vis vests for photographers, but if I’m doing my job properly the refs and skaters shouldn’t need to see me. I should be no more a hazard than a bench manager or an NSO.

I shoot in RAW mode to allow me to compensate for variable hall lighting later, and on the Canon 5D3 I write the files to 2 memory cards at the same time. That way if I have a card failure I won’t lose a whole bout. Paranoid again.

BoutDay ColourI set the camera colour balance manually for each hall – the Glasgow Caledonian Arc is 4200 Kelvin +6 magenta, more or less. Hall lights change colour as they warm up and each camera model has a slightly different colour response anyway. I calibrate initially with a Color Checker Passport.

I shoot about 1000 frames per bout. 900 on the 5D3 and 100 on the 7D. I can usually fill a 32GB card for each one. This stuff creates a lot of data.


BoutDay LightroomEditing happens in Adobe Lightroom on my MacBook Pro, taking around 6 hours per bout, and is powered largely by green tea and rock music.

BoutDay DrivesThe RAW files are copied from the cards onto a mirrored pair of 2TB hard drives (I’m on my 2nd pair of those now) and imported into Lightroom – 30 minutes to an hour.

I make basic colour balance and exposure adjustments to a typical image, and then paste those settings to all of the images in the set. I favour a neutral (perhaps slightly cold) image tone with fairly high contrast and the more saturated colours that come with that – 5 minutes.

I then run through all of the images and assess them. Those that make the cut are tagged, cropped, and fine adjustments made to colour and exposure. Borderline images are tagged red and reassessed when I’m finished – about 4 hours for 1000 images.

BoutDay GalleryOnce the initial selection is made I filter down to just those tagged shots, usually around 200, and check them again. I untag any weak, usually red tagged, images and export them as JPGs – 30 minutes.

BoutDayAfter one last check of the exported files they’re uploaded. Initially to Facebook and later to Google Plus and – 30 minutes.

Care and Feeding 

Mostly derby photographers don’t need a lot of looking after.  At single bouts and double headers in small halls, I just need a corner to stash my bags and occasionally a power socket to charge my phone. At tournaments and larger venues I really need somewhere secure (that the public can’t just wander into) to charge batteries and download full cards to my laptop. In Dallas there was a dedicated media room, but at other events I’ve had to hijack a corner of the NSO room or team area, which is only feasible if I’m allowed access. Otherwise I have to carry everything that I don’t want to turn my back on around with me all day.

In general we’re a pretty dedicated bunch. Like most of Derby, it’s a reasonably expensive thing to do, is quite time consuming, and there’s absolutely no money in it. There’s just no market for Roller Derby photographs, so anyone who is doing this regularly is doing it for the love of the sport. Or like me, for the afterparties and the hugs.

DaveMc, Feb 2015

Travel Tip

Dallas1A technology tip for those planning a trip to somewhere far away and unfamiliar. Grab some offline map data on WiFi before you go, and you’ll be able to use that map when you have data turned off on your phone.

You are going to remember to turn background data off before you leave, aren’t you?

On and Android device, find the place you want in Maps, for example (totally at random) Dallas. You may also be able to do this on a fruit based device, but I don’t have one so I’ll have to leave that as an exercise for the reader.

Tap on the search box and you’ll get a menu with ‘Save map to use offline’ at the bottom. Tap on this.

Dallas3Select the area you want – anything up to 50km square – and click Save. You’ll now have that map available for use offline. You won’t be able to search for places or calculate a route as you need a data connection for that, but you will be able to use it as an old school map.

Adderby Family

Adderby FamilyEvery year at Halloween, Glasgow Roller Derby play Rainy City Roller Girls. This year the fine people at GRD decided that a suitably spooky Halloween photo was needed for the bout poster, so after much plotting and scheming it was decided that the Addams Family was the way to go. I think the idea of me as Cousin It was the clincher here, but I could be wrong.

Roles were bagsied and assigned, costumes were arranged and costructed, and a location was found. The following week we all arrived at Titan Props in Glasgow and raided the weapons, stuffed animals and electric char departments for suitable accessories. These shots were the results. I’m really rather proud of them, even if I am in one two of them.

The Halloween bout is on Saturday the 26th of October 2013 at the Glasgow Caledonian ARC. There will be flat track roller derby, cake and Halloween costumery. Tickets can be purchased on the door or in advance here.

Featuring Beav, Gill.I.Am, Prawn, Meg, Hazard, Studley and Habs. Guest starring Submarine and yours truly. Additional spooky support by Maul.



Boogie2A few things are pretty much guaranteed at Roller Derby bouts: wheels, hits, action and dancing. Now there are usually people around with video cameras, but somehow the low tech approach with DSLR shooting a few frames per second seems to fit. Wobbly jerky fun.

Packing for Toronto

World Cup Gear

On Thursday morning I leave for Toronto to shoot the first Roller Derby World Cup with Team Scotland. Weight is an issue, so I have to travel light.

Yea, right.

It’s not just camera and film any more. These days there’s also the laptop and the graphics tablet and the image viewer and the hard drives and the batteries and the memory cards. And don’t forget the chargers. And all of the cables.

I did stick a light meter in there as well, just for the sheer nostalgia of it.

Really looking forward to seeing so many teams in such a shot space of time. Lots to shoot, edit and post while I’m there. Possibly not a lot of time for sleep.

If you’re there and you see an excited and slightly overwhelmed Scottish photographer please give him a wave and say Hi.


Glasgow Caledonian ARC Lighting Problems

For a while now I’ve been struggling with exposure and colour balance problems when shooting roller derby at the Glasgow Caledonian ARC. Every so often a shot will be underexposed and usually of a slightly warmer colour temperature than the shots next to it. At first I thought this was a a problem with the camera’s exposure system, but when shooting on manual I’m getting the same problem – two shots taken seconds apart, with the same camera settings, can have different exposures. It doesn’t happen a lot, but it has resulted in the loss of some good shots.

These two unedited shots were both taken with an exposure of 1/200th of a second at f/2.8, but the second one is about a stop darker than the first and is slightly warmer – look at the colour of the floor and wall.

Sometimes the underexposure is much worse, but this was the best side-by-side example I could find.

It took me a while to figure out what was going on here, but eventually I remembered that when I was shooting with slower shutter speeds I noticed something odd about the lighting. It flickers.

 This can be seen best in this detail crop of this panning image, taked with an exposure of 1/40th of a second at f/4.0. Look at the faces in the background – each one is repeated 3 times. So during the exposure the overhead lighting flashed 3 times.

My guess is that the lights are flashing about 100 times a second. Way too fast to be visible to the human eye, but if a camera shutter is set to an exposure shorter than this then there is a danger of catching the lights when they’re at the low point of their cycle, underexposing the image. As dimmer lights tend to be warmer, this would also account for the shift in colour temperature.

Unfortunately the slowest shutter speed that completely freezes the motion is about 1/200th of a second. Dropping this to 1/100th of a second to avoid the exposure issues results in more shots lost to blur than would be lost to underexposure.

Other than using flash, which I don’t really like doing, there’s not a lot that can be done about this other than avoiding shutter speeds faster than 1/200th of a second as this is likely to make the problem worse.

So far I’ve not encountered this problem anywhere else I’ve shot, so it seems to be quite an unusual feature of the ARC lights.


Pivots of the Caribbean

Next Saturday, 26/11/11, I’ll be travelling to Dundee to photograph the Silvery Tayzers playing the Fair City Rollers Fear Maidens. This will be my last shoot before I leave for Toronto to shoot Team Scotland playing in the first roller derby world cup.


GRG Home Teams Final

The last game of the Glasgow Roller Girls 2011 season, the Home Teams Final between the Death Stars and the Bad Omens is next weekend at the Glasgow Caledonian ARC.

I’ll be there to photograph the bout and eat cake. If you’ve not been to a roller derby game before, attendance is highly recommended. You can pre-purchase tickets here or pay on the door.

Hope to see you there. I’ll be the hairy one with the camera running about like an idiot.



I’m a pretty terrible blogger, but as I’ll be heading out to Toronto in a few weeks to cover the Team Scotland competing in the first Roller Derby World Cup I thought I might put in some extra effort and make the occasional update here.

If I can arrange internet access when I’m there I’ll be uploading photographs of the games before I get home. Watch this space.