Advice for Better Film Scanning
Being able to successfully digitise film images using a film scanner is something of an art and can be very frustrating. Part of the reason for this is that people fail to appreciate and take control of all the variables involved. This article discusses several ideas that will help you enjoy better film scanning and improved results. Testing and integrate these with your own workflow could see your film scanning significantly.
Three Parts to the Solution
The important point that many people fail to recognise is that their results are not just down to the quality of the scanner they use. This though is only one element of the puzzle. To achieve the best results when scanning film, you need to consider:
- Scanning Software
- Scanner Hardware
- Film Selection
By carefully optimising each of these you can achieve very impressive results. In this article we are going to consider each of these areas.
Consider the Software you use. Yes, you need to master how to use this to control your scanner, but there are some not so obvious points. Did you know that even when scanning optimally, different software packages will produce noticeably different levels of quality? Consider the following example of the same image scanned using an Epson V700 flatbed scanner.
VueScan is a third-party package that supports many current and obsolete scanners. When used properly it will produce high quality scans and in my own testing has consistently.
A similar situation exists with SilverFast, another third-party scanning application. Here my testing shows the SilverFast software produced better results than the Epson software but the difference between SilverFast and VueScan is marginal. Where SilverFast scores over VueScan is that its scans exhibit greater contrast, which make them appear sharper and more detailed at first glance. You can improve the VueScan images further by applying a micro contrast adjustment.
Unfortunately, some scanners, particularly flatbeds, have an image registration problem in that the scan head doesn’t return to the same position for the start of each scan or vibrations from the stepper motor can cause the film to move position. The result can be a soft or blurred scan when performing multiple samples and the higher the number of samples taken, the greater the risk this problem will occur.
In short, you will need to find the best software to match your scanner and scanning needs. Be sure to make different test scans and use the more advanced features. Also, be sure to scan the types of film you will be shooting as this can also affect the results you will produce, as set out later in this article. Don’t assume the software that came with the scanner is the best option and it should go without saying that you need to learn how to control the scanner properly.
Find out more about VueScan.
Find out more about SilverFast.
The scanning hardware plays a large part in the quality of the scan produced. Many scanners, particularly flatbed scanners don’t produce the claimed resolution. This is an issue with many flatbed scanners, but it may also affect some dedicated film scanners. Take my Epson V700 as an example, although the resolution says 6,400ppi (points per inch), much of this is soft and not usable. In resolution tests, the scanner has more like a 2,400ppi optical resolution and scanning beyond this resolution just gives you a bigger file.
If you want to check out the results for your scanner or a model you are you are considering purchasing, do visit the ScanDig website for scanner test results. The information on this site appears accurate and mirrors real life results. Many other websites I have visited for scanner reports seem to give an overly optimistic view of scanner capability. This may in part be down to sample variation in scanners or perhaps manufacturers providing known good test units for reviews.
But the image resolution isn’t just down to the scanner, it’s also affected by the film you’re scanning as well as the software used (as mentioned previously). By way of an example, when I use VueScan I can select the scan resolution from a dropdown list with options such as 3,200ppi and 6,400ppi. If I select a custom value that’s not in the list, I can detect artefacts in the resulting scan when viewed at 100% magnification. What I see suggests that the selected resolution achieved by the scanner (or software) results from enlarging a lower resolution scan. You should check this with your own scanner and software.
The VueScan software discussed above includes a size reduction feature that allows you to scan an image at a high resolution and then automatically down-sample this to a smaller image. The advantage of this is that you can achieve a higher quality image than simply scanning at a given resolution. This is well worth testing with your own scanner if you use VueScan.
Another factor to be aware of with scanners is the DMax. This is effectively the dynamic range the scanner can cope with. The theoretical maximum value is 5 but in practice very few scanners can achieve near this. A value of 3.5 to 4.0 is much more typical. Flatbed scanners tend to have a lower DMax than dedicated film scanners. Sometimes you find scanner manufacturers will quote the theoretical DMax of their scanners rather than the official test results. Theoretical values are usually higher (sometimes by a large margin) than the test values.
When scanning, the DMax will limit your ability to produce good scans some types of film or at least make it very difficult to achieve acceptable results. One example of this is Velvia slide film where many scanners simply can’t penetrate the dark areas of the slide to capture detail. Other films such as print negative require a much lower DMax value to produce a good scan.
One technique that can use to improve the DMax of your scanner is HDR (if your scanner and software will support this). It works by creating multiple passes of the image, but each pass uses different levels of exposure. Typically, there are three scans; 1 over, 1 under and 1 correctly exposed. The software then blends the scans to produce an image with better dynamic range than the DMax would allow using a single scan.
This approach does work but often doesn’t produce a dramatic improvement. It also increases the scanning time as three passes of the image and one of these (the over exposure) is also slower to create the over exposure. The technique is also susceptible to the alignment issues mentioned earlier with the multiple exposure scanning. If your scanner and software support HDR scanning, do make use of it where necessary.
Film Choice for Scanning
Films generally split into three categories: black and white, colour negative and colour slide. Each have characteristics that can make a film ideal for scanning or present you with problems. Which is which will depend largely on the features and capability of your scanner.
Black & White Negative Film
Black and white negative films tend to have a low DMax demand, allowing scanners with a low DMax to capture a large range of tonal values. These films also tend to appear sharp, often allowing you to capture lots of detail.
If you want to shoot black and white but want to enjoy the benefits of automatic dust removal, you should consider a dye based film such as Ilford XP2. Alternatively, you can shoot colour film and convert this to black and white.
I personally find it better to clean my film first using a film cleaner and then use a dust blower prior to scanning. The resulting scan can then be spotted using Lightroom or Photoshop. This may take slightly more time than applying ICE but it produces a higher quality result.
Colour Negative Film
Like black and white, colour negative film can be well scanned using only a limited DMax. Both colour negative or black and white film can also deal with higher dynamic range in the scene being captured. With subjects such as Landscapes this often means you don’t need to worry about exceeding the capabilities of the film and blowing the highlights. Unlike digital, where bright values turn to pure white and lose detail suddenly, film highlights tend to tail off and detail is lost in a more controlled (and appealing) way.
There are two downsides to Colour Negative film. The first is that these films tends not to be very sharp in comparison to Black and White or Slide film. If you want to make a large scan from your frame, you need to have a physically large negative to scan from. This means Medium or Large Format. Trying to make a large image from a 35mm frame can be quite demanding and will require a good film scanner. Flatbed scanners often can’t achieve the level of optical resolution necessary so end up producing soft scans.
Another problem facing you is correcting the colour mask that most print negative films use. If you look at a negative, you will notice that the film is orange and without true colours. When you scan a piece of this film the scanning software needs to remove this colour mask. Even where your scanning software has a colour profile to do this, the profile often doesn’t work well. This can mean additional processing post capture of the scan, just to achieve a good colour balance.
To deal with removal of the colour mask, try using different colour negative profiles in your scanner software. For example, I have achieved good results from applying a Kodak Ektar correction to a Kodak Portra scan.
You can also use special colour correction software such as Color Perfect. This is able to process an uncorrected version of a scan to remove the colour mask and make colour corrections. This is very powerful software although personally I have struggled to achieve good results and find the software difficult to use.
Find out more about Color Perfect.
My own alternative solution is to use Color Washer from PhotoWiz. This is applied to the scan after the scanner software has corrected the colour mask. Color Washer uses automated settings to achieve a good white balance as well as offering a number of colour correction variations. The results are good and it’s very easy and quick to use.
Find out more about Color Washer.
The final category of film is slide film. This tends to be much sharper and more detailed than either black and white or colour negative film. It’s usually very fine grained and can give results similar to a digital image in terms of detail and sharpness. As well as being very sharp and responding well to sharpening in post-production, the images produced tend to exhibit great colour and saturation.
Slide film also tends to produce much denser images than black and white or colour negative film. This can make scanning them very tricky and almost impossible if your scanner doesn’t have a good DMax. Some films have such dark shadows (e.g. Fuji Velvia) that detail can be completely lost in areas of shadow as these turn completely black in the scanning process. This is one reason some photographers advocate rating Velvia at ISO40 rather than ISO50.
Good Practice When Scanning Film
We have covered a lot of ground but there are still a few other points of good practice to consider. When scanning film photography, the following points might help you achieve better scanning results.
- Don’t enlarge scans, they don’t enlarge anywhere as near as well as digital images. Scan at the resolution you need or larger. You can always down sample if you need to but try to avoid increasing the image size after the scan. This means your scanner and its true optical resolution will become the limiting factor in determining the size of print you can realistically achieve.
- Review your exposure technique when shooting with film. For slide film you really need to get the exposure spot and possibly over expose very slightly to help lighten shadow areas. You definitely need to avoid blowing the highlights in the slide, which is something that can happen very quickly, especially in Landscape Photography. Remember, the scanner is likely to struggle pulling detail from dark areas of the slide so if you can lighten these areas it will make the task easier. Equally, if you over expose, you can suffer from areas that become pure white, so losing detail. This will possibly do more to harm the aesthetics of the image than deep shadow areas.
- When shooting with negative film (Colour and B&W) you have more latitude to over expose. Films such as Kodak Portra will allow you to overexpose by quite a lot before the highlights loose detail. Be sure to use this if your scanner has a low DMax as it can open up heavy shadow areas making them easier to scan.
- Broadly speaking there are two types of light sources used in scanners (LED and Fluorescent). Some films, especially B&W don’t respond well to LED. These light sources can make grain appear overly harsh so you might need to do something to soften the resulting scan.
- We have already discussed the optical resolution of the scanner and how this can limit the size of usable image. For example, if the scan is only good up to 2,400ppi, a 35mm slide will only produce a file that’s a little less than 2,400 pixels on the short side (or around 8 inches when printed at 300dpi). Now scan a 6cm x 6cm medium format image at the same resolution and the image is around 19 inches high and wide. A print of this size would look large. Contrast this with an XPan slide which would be around 8 inches high but 19 inches wide. Despite the XPan image having the same width as the medium format slide, the print height of 8 inches would make it appear small in relation to the 6cm x 6cm film.
- Consider calibrating your scanner. If you want to Calibrate your scanner using VueScan, this article should help.
We have covered a lot of ground in this article but we have only begun to touch on some of the variables that will help you produce better film scans. Whilst other people’s tips will help, nothing replaces the value of your own experimentation.
If you're shooting black & white film, you may be interested in my alternative scanning approach for sharper scans.
If you have any tips or advice of your own for better film scanning, please share them in the comments for this article.