Month: June 2020

How to Process Black-and-White Film

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A few weeks ago, I came very close to investing in an Ilford/Paterson Starter Kit so that I could process film at home. I have four exposed rolls of 35mm HP5+ sitting on my shelf, and I thought that developing them at home might be a nice way to kill a bit of lockdown time. However, I still wouldn’t be able to print them, due to the difficulties of creating a darkroom in my flat. And with lockdown now easing, it probably won’t be long until I can get to Holborn Studios and hire their darkroom as usual.

So in this article I’ll talk through the process of developing a roll of black-and-white 35mm, as I would do it in the Holborn darkoom. If you haven’t already, you might want to read my post about how film works first.

 

You will need

 

Loading the developing tank

Holborn Studios’ darkroom, run by Bill Ling, displays this handy reminder.

The first step is to transfer the exposed film from its cassette – which is of course light-proof – into the Paterson tank, which is designed to admit the developing chemicals but not light. This transfer must take place in complete darkness, to avoid fogging the film. I’ve always done this using a changing bag, which is a black bag with a double seal and elasticated arm-holes.

Start by putting the following items into the bag: the film cassette, scissors and the various components of the Paterson tank, including the spiral. It’s wise to put in an empty film canister too, in case something goes wrong, and if the tail of your film isn’t sticking out of the cassette then you’ll need a can opener as well.

Seal the bag, put your arms in, and pull all the film out of the cassette. It’s important NOT to remove your arms from the bag now, until the film is safely inside the closed tank, otherwise light can get in through the arm-holes and fog the film.

Use the scissors to cut the end of the film from the cassette, and to trim the tongue (narrower part) off the head of the film.

Paterson Universal Developing Tank components, clockwise from the white items: developing reels or spirals, tank, light-proof lid, waterproof cap, and agitator – which I never use. In the centre is the core.

Now we come to the most difficult part, the part which always has me sweating and swearing and regretting all my life choices: loading the film onto the spiral. I have practised this with dead film many times, but when I’m fumbling around in the dark of the changing bag it’s a hundred times harder.

It’s hard to describe loading the spiral verbally, but this blog post by Chris Waller is very clear and even includes pictures. (Chris recommends cutting a slight chamfer onto the leading corners of the film, which I shall certainly try next time, as well as using your thumbs to keep the film flat on its approach to the reel.)

If you’re working with 120 film, the loading process is very slightly different, and this video describes it well.

Once the spiral is loaded, you can thread it onto the core, place the core inside the tank, and then put the lid on. It is now safe to open the bag.

 

Developing

Developing time info displayed at Holborn Studios

Holborn Studios’ darkroom is stocked with a working solution of Kodak HC-110 developer, but if you don’t have this luxury, or you’re not using the Ilford Simplicity packs, then you’ll need to make up a working solution yourself by diluting the developer according to the manufacturer’s instructions. For HC-110 dilution B, which is what Holborn uses, it’s 1+31, i.e.one part concentrated developer to 31 parts water. The working solution has a limited shelf life, so again consult the manufacturer’s instructions.

Further dilution is required at the point of development, at a ratio of 1+7 in this case, but once more this may vary depending on the chemicals you choose. For one roll of 35mm, you need 37.5ml of the HC-110 dilution B, and 262.5ml of water for a total of 300ml.

The developing time depends on the type of film stock, the speed you rated it at, the type of developer and its dilution, and the temperature of the chemicals. Digital Truth has all the figures you need to find the right development time.

Agitating

I was taught to ensure my water is always at 20°C before mixing it with the developer, to keep the timing calculations a little simpler. At this temperature, a roll of Ilford HP5+ rated at its box speed of ISO 400 needs five minutes to develop in HC-110 dilution B. Ilford Delta, on the other hand, needs a whopping 14.5 minutes to process at its box speed of 3200.

Once your diluted developer is ready, pour it into the Paterson tank and put on the cap. It is now necessary to agitate the chemicals in order to distribute them evenly around the film. My technique is inversion, i.e. turning the tank upside-down and back again. Do this continuously for the first 30 seconds, then for 10 seconds every minute after that.

Inside the tank, your latent image is being transformed into an image proper, wherein every exposed silver halide crystal is now black metallic silver.

 

Fixing

Once the developing time is up, remove the cap from the tank, and pour away the developer immediately. At this point some people will say you need to use a stop bath to put a firm halt to the developing process, but I was taught simply to rinse the tank out with tap water and then proceed straight to fixing. This method has always worked fine for me.

After rinsing the tank, pour in enough fix solution (again prepared to the manufacturer’s instructions) to fill it completely. Put the cap back on, agitate it for 30 seconds, then leave it for ten minutes.

During this time, the fixer renders the film’s unexposed crystals inactive and water soluble. When the ten minutes is up, pour the fixer back into its container (it’s reuseable) and leave the tank under running water for a further ten minutes. This washes away the unused silver halide crystals, leaving only the exposed black silver corresponding with light areas of the scene, and just the transparent plastic base corresponding with the dark areas.

Squirt a little diluted washing-up liquid into the tank to prevent drying rings, then drain it. You can now open the tank and see your negative for the first time.

 

Drying

Remove the film from the developing spiral, taking care to only touch the ends and the edges. Squeegee the top part of the film, dry your hands, then squeegee the rest. This removes droplets which can otherwise mark the negative.

Now attach two hooks to the film, a light one at the top to hang it from, and a heavy one at the bottom to stop the film curling as it dries. Holborn Studios is equipped with a heated drying cabinet, but with patience you can hang a film to dry in any dust-free area.

When your film is dry, you can cut it into strips of six frames and insert them into a negative storage sheet.

You can now scan your negatives, or better still print them photo-chemically, as I’ll describe in a future post.

How to Process Black-and-White Film

Should DPs Own Equipment?

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Recently I discovered Tailslate, a podcast by DPs Ed Moore, BSC and Benedict Spence. The second episode focuses on equipment, and the two men discuss the pros and cons of having your own gear. I have some pretty strong feelings on this myself, so I thought I’d share them here.

I owned equipment for the first 17 years of my career. I was fortunate that at the time I first went freelance (late 1999) I had a small inheritance which I was able to invest in the wonderful new Mini-DV/Firewire technology that had recently emerged. I bought my first semi-professional camera, a Canon XM-1, along with a decent Manfrotto 501/520 tripod, a basic tracking dolly, sound gear, and for editing a PowerMac G4, Mini-DV/VHS deck and a pair of Yamaha MSP5 active nearfield speakers. (The speakers are the only things I still have, and I’m using them as I write, 20 years on. They are the best thing I’ve ever bought. Nothing else has ever served me for so long, so frequently and so reliably.)

Shooting on my Canon XL1-S back in 2003

Apart from the speakers, everything else got replaced every few years as it fell into obsolescence or simply packed up. The XM-1 was replaced with an XL-1S, then I moved onto HDV with a Sony A1, then onto DSLRs with a Canon 600D/T3i, then a Blackmagic Production Camera, which turned out to be my last camera.

Immediately you can see one of the key problems with owning equipment: the fast pace of technological progression and the need to upgrade regularly to keep up. But owning equipment had disadvantages even before the fast-paced digital revolution. In a fascinating Clubhouse Conversation from the American Society of Cinematographers, M. David Mullen, ASC recounts his own experience with gear:

I ended up never owning a camera package. Because of that, I shot mostly 35mm in my early days… People I know who bought a [super]-16 camera, they ended up shooting [super]-16 films for the next ten years or so. So you can get tied to your own equipment.

But there are benefits to owning kit, of course. Corporate clients expect you to provide the gear yourself or to hire it in without any fuss. Clearly the former allows you to make more money from these jobs.

My last camera, the Blackmagic Production Camera 4K

For creative jobs, things aren’t so cut and dried. Owning a camera will certainly get you more work of a certain type. That type is unpaid and low-paid. If you expect to charge a hire fee on your gear, forget it. The type of productions that want you to have your own gear is the type that can’t afford to hire, either from you or from a facilities house. They’ll expect you to come along and bring your gear for free.

We all need to do this type of work at the start of our careers, which is why owning equipment is great at that point. But ultimately I sold my Blackmagic in 2017 and didn’t replace it because I no longer wanted that type of work.

I think things are a little different if you can afford to own a high-end camera. I’m pretty certain that I’ve lost jobs in the past, despite being a better cinematographer than the successful applicant, because they had a Red and I only had a DSLR or a Blackmagic. If you can afford an Alexa then you might well be able to get quality jobs off the back of it, but most of us aren’t in that position!

A camera that I could never afford to buy

The best thing about not owning gear is that you’re free to select the best equipment to tell each particular story (budget and production mandates notwithstanding). Each production is different, and there is no single camera or lens set that is best for all of them. Resolution, high frame rates, colour science, contrast, sharpness, weight, size, cost – all these factors and more influence a DP’s choice, and it’s a critical choice to make. If you’re pushing your own camera or lenses to the production just so you can recoup some of the cash you spent to buy them, you’re doing the story a disservice.

In conclusion, whether or not to invest equipment depends on your budget and the type of work you want to do. But if you’re shooting a drama, even if you own equipment, you should be asking yourself what camera and lenses will best set the tone and tell this story.

Should DPs Own Equipment?

“Above the Clouds”: The Spoiler Blogs

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During 2016-2017 I blogged about the production of Above the Clouds, a comedy road movie which I shot for director Leon Chambers. It premiered at Raindance in 2018, closely followed by Austin Film Festival, where it won the audience award for Best Narrative Feature, the first of four gongs it would collect.

In two decades of filmmaking, Above the Clouds is easily in the top five productions I’m most proud of. Since this January it has been available on Amazon, iTunes, Google Play and other platforms, and I highly recommend you give it a watch. DO NOT continue reading this blog unless you have, because what follows are two blog entries that I held back due to spoilers.

 

DAY 14

(from Week 3)

The script calls for Charlie to be seen sitting in the window seat of a plane as it rises quite literally above the clouds. This is another micro-set filmed in Leon’s living room, in fact half in the living room and half in the hall, to leave enough room for the lights beyond.

Although the view out of the window will be added in post, I need to simulate the lighting effect of bursting through the clouds. My plan involves a 1.2K HMI, and a 4×4 poly board held horizontally with a triple layer of 4×4 Opal sheets hanging from one edge.

We start with the HMI pointed straight into the window and the poly board held high up so that the Opal hangs in front of the lamp. As the plane supposedly rises through the cloud layer, Colin lowers the poly until it is below the level of the lamp, while Gary tilts the HMI down so its light skips off the poly (like sun skipping off the top of clouds) and bounces back up into the window. Gary then tilts the HMI back up to point straight into the window, to suggest further banking or climbing of the aircraft. This direct light is so hot that it bounces off the armrest of Charlie’s seat and gives a glow to her cheek which syncs perfectly with a smile she’s doing.

 

DAY 25

(from February 2017 pick-ups)

Today’s set is a dark room. A photographer’s dark room, that is. Not just a random dimly-lit room.

We begin with only the red safe-light in play. The wall-mounted practical has a 15W bulb, so it needs some serious help to illuminate the room. Micky rigs a 1K pup with Medium Red gel and fires it over the top of the set, above the practical. The effect is very convincing. Pure red light can make everything look out of focus on camera, which is why I chose the slightly magenta Medium Red gel, rather than the more realistic Primary Red. The colourist will be able to add some green/yellow to correct this.

During the scene, Naomi pulls a cord and the normal lights come on. These are two hanging practicals, fitted with dimmed 100W tungsten globes. In a very similar set-up to yesterday, we use a 2K with a chimera, poking over the set wall on the camera’s down-side, to enhance and soften the practicals’ light.

To read all the Above the Clouds blogs from the start, click here.

“Above the Clouds”: The Spoiler Blogs

How Digital Sensors Work

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Last week I delved into the science of how film captures an image. This time we’ll investigate the very different means by which electronic sensors achieve the same result.

 

CCD

In the twentieth century, the most common type of electronic imaging sensor was the charge-coupled device or CCD. A CCD is made up of metal-oxide-semiconductor (MOS) capacitors, invented by Bell Labs in the late fifties. Photons striking a MOS capacitor give it a charge proportional to the intensity of the light. The charges are passed down the line through adjacent capacitors to be read off by outputs at the edges of the sensor. This techniques limits the speed at which data can be output.

My first camcorder, an early nineties analogue 8mm video device by Sanyo, contained a single CCD. Professional cameras of that time had three: one sensor each for red, green and blue. Prisms and dichroic filters would split the image from the lens onto these three CCDs, resulting in high colour fidelity.

A CCD alternates between phases of capture and read-out, similar to how the film in a traditional movie camera pauses to record the image, then moves on through the gate while the shutter is closed. CCD sensors therefore have a global shutter, meaning that the whole of the image is recorded at the same time.

CCDs are still used today in scientific applications, but their slow data output, higher cost and greater power consumption have seen them fall by the wayside in entertainment imaging, in favour of CMOS.

 

CMOS

Complementary metal-oxide-semiconductor sensors (a.k.a. APS or active-pixel sensors) have been around just as long as their CCD cousins, but until the turn of the millennium they were not capable of the same imaging quality.

Each pixel of a typical CMOS sensors consists of a pinned photodiode, to detect the light, and a metal-oxide-semiconductor field-effect transistor. This MOSFET is an amplifier – putting the “active” into the name “active-pixel sensor” – which reduces noise and converts the photodiode’s charge to a voltage. Other image processing technology can be built into the sensor too.

The primary disadvantage of CMOS sensors is their rolling shutter. Because they capture an image row by row, top to bottom, rather than all at once, fast-moving subjects will appear distorted. Classic examples include vertical pillars bending as a camera pans quickly over them, or a photographer’s flash only lighting up half of the frame. (See the video below for another example, shot an iPhone.) The best CMOS sensors read the rows quickly, reducing this distortion but not eliminating it.

Today, all the major cinema cameras use CMOS sensors, from Blackmagics to Alexas. Medium format stills cameras clung on to CCD technology longest for that higher image quality, but even these are now CMOS.

CMOS sensors are cheaper, less power-hungry, and not suspectible to the highlight blooming or smearing of CCDs. They are also faster in terms of data output, and in recent years their low-light sensitivity has surpassed CCD technology too.

 

Beyond the Sensor

The analogue voltages from the sensor, be it CCD or CMOS, are next passed to an analogue-to-digital convertor (ADC) and thence to the digital signal processor (DSP). How much work the DSP does depends whether you’re recording in RAW or not, but it could include things like correcting the gamma and colour balance, and converting linear values to log. Debayering the image is a very important task for the DSP, and I’ve covered this in detail in my article on how colour works.

After the DSP, the signal is sent to the monitor outputs and the storage media, but that’s another story.

How Digital Sensors Work

How Film Works

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Over the ten weeks of lockdown to date, I have accumulated four rolls of 35mm film to process. They may have to wait until it is safe for me to visit my usual darkroom in London, unless I decide to invest in the equipment to process film here at home. As this is something I’ve been seriously considering, I thought this would be a good time to remind myself of the science behind it all, by describing how film and the negative process work.

 

Black and White

The first thing to understand is that the terminology is full of lies. There is no celluloid involved in film – at least not any more – and there never has been any emulsion.

However, the word “film” itself is at least accurate; it is quite literally a strip of plastic backing coated with a film of chemicals, even if that plastic is not celluloid and those chemicals are not an emulsion. Celluloid (cellulose mononitrate) was phased out in the mid-twentieth century due to its rampant inflammability, and a variety of other flexible plastics have been used since.

As for “emulsion”, it is in fact a suspension of silver halide crystals in gelatine. The bigger the crystals, the grainier the film, but the more light-sensitive too. When the crystals are exposed to light, tiny specks of metallic silver are formed. This is known as the latent image. Even if we could somehow view the film at this stage without fogging it completely, we would see no visible image as yet.

For that we need to process the film, by bathing it in a chemical developer. Any sufficiently large specks of silver will react with the developer to turn the entire silver halide crystal into black metallic silver. Thus areas that were exposed to light turn black, while unlit areas remain transparent; we now have a negative image.

Before we can examine the negative, however, we must use a fixer to turn the unexposed silver halide crystals into a light-insensitive, water-soluble compound that we can wash away.

Now we can dry our negative. At this stage it can be scanned for digital manipulation, or printed photo-chemically. This latter process involves shining light through the negative onto a sheet of paper coated with more photographic emulsion, then processing and fixing that paper as with the film. (As the paper’s emulsion is not sensitive to the full spectrum of light, this procedure can be carried out under dim red illumination from a safe-light.) Crystals on the paper turn black when exposed to light – as they are through the transparent portions of the negative, which you will recall correspond to the shadows of the image – while unexposed crystals again remain transparent, allowing the white of the paper to show through. Thus the negative is inverted and a positive image results.

 

Colour

Things are a little more complicated with colour, as you might expect. I’ve never processed colour film myself, and I currently have no intention of trying!

The main difference is that the film itself contains multiple layers of emulsion, each sensitive to different parts of the spectrum, and separated by colour filters. When the film is developed, the by-products of the chemical reaction combine with colour couplers to create colour dyes.

An additional processing step is introduced between the development and the fixing: the bleach step. This converts the silver back to silver halide crystals which are then removed during fixing. The colour dyes remain, and it is these that form the image.

Many cinematographers will have heard of a process call bleach bypass, used on such movies as 1984 and Saving Private Ryan. You can probably guess now that this process means skipping or reducing the bleach step, so as to leave the metallic silver in the negative. We’ve seen that this metallic silver forms the entire image in black-and-white photography, so by leaving it in a colour negative you are effectively combining colour and black-and-white images in the same frame, resulting in low colour saturation and increased contrast.

“1984” (DP: Roger Deakins CBE, ASC, BSC)

Colour printing paper also contains colour couplers and is processed again with a bleach step. Because of its spectral sensitivity, colour papers must be printed and processed in complete darkness or under a very weak amber light.

 

Coming Up

In future posts I will cover the black-and-white processing and printing process from a much more practical standpoint, guiding you through it, step by step. I will also look at the creative possibilities of the enlargement process, and we’ll discover where the Photoshop “dodge” and “burn” tools had their origins. For those of you who aren’t Luddites, I’ll delve into how digital sensors capture and process images too!

How Film Works