Slashed Canvas :: Composed & Shot

When comparing DSLR technology to film some people seem to imply that 35mm film will soon go the way of the dinosaur. But in truth, film is different and has its ongoing advantages too.

It is often said that colour negative film is very forgiving of exposure errors. When reasonably underexposed it's often possible to rescue the image. But even when negative film is exposed properly, it hasn't fully realised its potential.

Highlight, grain and sharpness
The highlight detail in colour negative film develops much more than the detail in the shadows. This means negative film can easily withstand a stop or two of overexposure. Overexposed negative film will easily retain more highlight detail than slide film or DSLRs, and the detail in the shadows will be increased, too.

The layers and chemicals in overexposed negative film will work together to actually reduce grain and enhance sharpness. But it's important to remember that pushing the film too far will cause these gains to break down. So just a stop or two is ideal.

Reducing colour casts
Colour casts are significantly reduced when negative film is overexposed. When exposed normally to daylight, each layer gets sufficient exposure, but if the prevailing light source is unbalanced, an unpleasant cast will result because one or more of the layers gets too little exposure.

Overexposure will boost the starved layer without harming the others. So the orange glow so typical of indoor light and the greenish cast from fluorescent light will be less noticeable. Again, too much exposure will undermine the benefits.

Why Scan Colour Negative Film?

Gone are the days when 35mm negative film was known simply as "print film", preferred by amateurs for their economy prints and unpopular with pros. Even though viewing slides properly isn't exactly convenient, for decades many advanced amateurs have preferred them partly because the alternative, negative film, has to be printed and is therefore a second-generation image. Today, with the introduction of good quality consumer film scanners†, the balance has shifted significantly. Both slide and negative film originals can be scanned in great detail and the resulting images digitally printed. This process has effectively narrowed the traditional gap between colour negative film and slide film. This is good news for amateurs who don't want to project slides and those who would rather shoot sharp, high quality colour negative film.

The industry-standard reproduction process scans slide film with an image sensor, the light passing through to record as much detail and tonal quality as possible, although the loss of shadow detail in the original and on the printed page is not to everyone's taste. Unfortunately, colour negative film is not suitable for this expensive, professional process, which is one reason why slide film has been the preferred choice of book publishers. However, good consumer film scanners allow the modern amateur to work at home on original images. Scanning and image-editing software programs can be used together to impressively control the tonal range, contrast, colour saturation and grain. In fact, it's now possible to minimise the effects of grain so that it's not an issue in the final print at typical viewing distances.

Working on a colour negative prescan.

Shooting fine-grained colour negative film allows you to hold excellent shadow detail while largely avoiding the pitfall of the lost highlights that can be a regular problem with slide film and DSLRs. As a consequence, exposing colour negative film properly is less difficult and the sharp and tonally rich negatives give you more information to work with in the digital darkroom where tonal and colour information in 20+ megapixel images can be manipulated creatively to produce quality, saturated digital prints. As with all digital images, it's also possible to produce impressive black and white prints from colour originals. The only real problem with shooting colour negative film is getting quality scans that make good use of colour and tonal information across the range — not everyone is prepared to invest in a decent 35mm scanner that captures very good highlight and shadow detail (dynamic range), and some labs may not produce the results you need.

Slide Film or Colour Negative Film, or DSLRs?

Particularly in the context of scanning for prints, what's the real difference between 35mm slide film and colour negative film? And, to logically expand the discussion a little further, are there any tangible advantages to shooting with a DSLR rather than either of the film types? We can quite easily reach a conclusion at the very beginning. Despite the fact that the fruitless Slide Vs Neg Vs Digital Sensor debate occasionally raises its head in photo forums, there is in truth no definitive answer that will suit everybody. For the discerning small format amateur — and the SLR amateur photographer is the overall context of this site — it's often a matter of personal choice, with advantages and disadvantages built into all three options.

Clearly DSLR photography is very convenient with more shooting options geared to particular styles. Photojournalism, general action or sports photography, aspects of wildlife photography and even the more casual pursuit of that special image will all benefit from digital technology. Although consumer DSLRs are more expensive than comparable film SLRs, there are no film and processing costs to take into consideration, and for many photographers, amateur and professional, this is a significant advantage. And digital is immediate, with no long delay beween shooting and viewing. However, a 35mm amateur photographer with a very different style of photography — landscape, or still-life, for example — may not see these benefits as particularly appealing. A lot depends on the individual's approach and output, and for many today 35mm film is still an attractive and viable option, especially if the film can be scanned at home and manipulated methodically in image-editing software.

Various terms are used to describe the inherent properties of film. The curious amateur photographer will read about exposure latitude, dynamic range, tonal range and even scenic range. To simplify this diversity you only need to understand that slide film and negative film respond differently to the tonal values in the scene you intend to record. Or, to put it another way, the range of illumination in the scene, all the way from the darkest shadows to the brightest highlights, will be recorded slightly differently depending on the choice of film, negative or postive. A film's ability to retain shadow and highlight detail is known as its dynamic range.

If quality is usually important, it's best to scan negatives or slides yourself. The image on the left is an auto scan made when the film was processed at a local lab. The poor result is almost certainly due to automatic processing. The manual scan of the colour negative frame has deliberately held the delicate highlight detail (too fine to be seen on the histogram, above right). Shadow detail is excellent. Neither image has been edited. The turn-around time at a mini-lab can be exceptional, digital prints from your prepared files should be excellent and a CD of auto-scanned images will be very useful for reference, but film processing standards can vary. Incidentally, although the Fuji Reala film was 3 months out of date and had been poorly stored, it produced quality negatives. And, if you're interested, the blooms belong to the Calico Bush (North America).

Colour negative film's propensity to hold very good tonal values accounts for its much wider exposure latitude. Colour negative film has lower contrast properties than slide film and will cope quite well with highlight and shadow detail throughout the frame, perhaps up to five stops of light: three overexposed and two underexposed. In real world amateur photography this means that properly exposed fine-grained colour negative film will capture very good shadow detail while also retaining subtle tonal gradations in the brighter areas of the scene – clouds, for example, or sunlit Caucasian skin tones. So, because negative film copes so well with highlights, before you take your shots you should try to make sure you're capturing as much relevant detail in the shadows as possible. Colour negative film, with its broad gradations of tone, is ideal for scanning because there's a lot of useful information across the range to work with on the computer.

However, when compared to slide film, colour negative film's wide exposure latitude usually means the recorded image has less contrast and saturation – it appears to have less bite! More than that, the orange mask built into negative film can present unique problems, with consumer scanners offsetting its effects with varying degrees of success. As a result, getting the best colour balance may occasionally take a little effort. In the final analysis, however, scanning techniques and image-editing software can inject punch and zest into digital images from colour negatives and this in turn means more vibrant prints. In other words, you can give them more bite if you wish.

Positive (slide) film typically has more lively contrast and vivid colour than negative film. It also exhibits smoother tonal blends and remarkably fine grain. It's unfortunate then that it struggles to hold detail in the highlights, and very dark shadows can be rendered almost black. Before exposing slide film it's best to make sure preference is given to brighter areas of the scene. It's possible to compensate for the wide contrast range in a landscape scene by using graduated filters. The slide photographer can also use typical image-editing techniques that impressively expand the exposure latitude of any scene by combining two or more scanned images.

Frustratingly, digital sensors share slide film's highlight problems but will get more from the shadows, as illustrated elsewhere in this site. Shadow retention will be particularly good if the exposure, when appropriate, is routinely pushed just short of blown for major brighter detail, and unprocessed and uncompressed data is captured rather than JPEG. If this isn't possible and the subject being photographed allows for it, two or more images can be used to substantially expand the range, as mentioned above. Sensor pixels, or light receptors, wrestle with bright light because their response to it is not gradual. Instead they peak quite quickly, totally losing highlight data. Digital camera manufacturers are working on this problem but to date (2010) the application of their technological advances has been less than ideal. It's certainly an irritating problem that makes some digital exposures quite tricky, a bit like shooting slide film, and it's likely to be an integral part of DSLR technology for quite some time to come.

Regardless of how you produce your digital images, it's worth remembering that considerable tonal information will always be lost in the print, regardless of how that print is made. Various software techniques can be used to partially compensate for this loss by selectively expanding the range of tones. The result, if required, would be a print with shadow and highlight detail that better reflects the original digital image. This underscores how important it is to familiarise yourself with the finer details of digital image processing and so make proper use of the digital darkroom. A best-quality JPEG image converted to a lossless format for editing has more latitude than you might expect and unprocessed data straight from the camera (RAW) will allow you additional control, when necessary.

UNDERSTANDING DIGITAL EXPOSURE:

GENERAL:

SCANNING 35MM FILM

And the significance of Colour Negative Film

The Negative Advantage

Why Scan Colour Negative Film?

How big a problem is grain? Above left is 100% selected detail of a 4000 ppi Fuji Reala 35mm scan made without using additional software routines to minimise the grain (note the ring on the finger). Shot wide open with a Canon 70-210mm consumer lens. Scanner: Minolta Dimage Scan Elite 5400.

Working on a colour negative prescan.

In image-editing software even a bland digital image of a hazy scene (in this case from a DSLR) can be made to look like saturated slide film, if that's what you like. Click for more detail.

Slide Film or Colour Negative Film, or DSLRs?

† 35mm film attachments for quality flatbed scanners cannot compete with dedicated 35mm film scanners.