A 35mm film does not have megapixels because films do not need to bother with megapixels.
Pictures taken through films do not have pixels. Each frame of a celluloid film is a complete picture. The pixels may appear only if the picture is digitally scanned, and that depends on the quality of the scan!
This article dives into further information about films, digital film scans, digital resolution of films, the difference between film and digital cameras and the resolution of a 35mm slide.
A film or a photographic film is a strip of transparent film base coated on one side with a gelatin emulsion containing small light-sensitive silver halide crystals.
The crystals determine the sensitivity, contrast and resolution of the film. The photographic film is being used to capture images by exposing the layers of plastic to light.
This plastic has a coating with an emulsion which forms an image when exposed to light. After clicking the photograph, the film is then introduced to a series of chemical processes to form a visible image; the visible image could be negative or it could be reversed in brightness.
Even so, the negative image is then printed on sensitive paper.
Some photographers still choose to use film and then scan the images to get a digital file. When you scan a photographic film, including the negatives and film slides to create a digital image based on the input, it is called a digital film scan.
A digital film scanner is used to carry out this process. These devices are being used to scan different types of films such as developed photographs, negatives and small slides. Some scanners can also scan entire reels of films to create a digital video file.
During digital film scans, there are a few things to bear in mind to ensure that the digital image is suitable:
- Make sure that the film images are not over-exposed or un-sharpened, as they will only worsen after scanning. Before scanning, you can improve tonal range and colours.
- Ensure that the originals are clean before scanning – so that the dust and scratches are not seen in the scanned image. One of the ways you can ensure this is by cleaning the negatives and slides with a cloth or using a blower brush to remove the dust particles before the scan.
- Before scanning the actual images, do a few trials by trying various scanning settings to determine which you want.
The digital resolution of the film might fluctuate based on different variables such as:
- Whether the film is black & white or colour.
- What is the ISO value of the film, which refers to the film’s speed or light sensitivity?
- The type of the grain – whether it is a tabular grain film or a traditional grain film.
- The brand and the quality of the film.
- The visual quality of a digital photograph is in the resolution of the image, that is megapixels.
- In digital photography, a higher number of pixels in an image state that the picture is denser and high in resolution.
- Digital photography has much less grain/noise than film at moderate sensitivity, thus giving an edge in image quality. Yet, digital cameras can display more noise if the sensitivity settings are high.
- Noise in digital photography can result in colour distortion or weird patterns, especially in indoor lighting. But, most digital cameras apply noise reduction to long exposure photographs to lessen the noise due to pixel leakage.
- In comparison to film, digital cameras offer much higher speed which allows the camera to perform better in low light or short exposures. The speed of the digital camera can be adjusted at any time.
- The film is not affected by pixels, although the pixels may become visible upon enlargement, creating particles known as grain in the final output.
- The resolution of the film depends upon the film speed and the area of the film used to record the image. For example 35mm, medium format or large format.
- Professional film cameras use medium and large format films as they can record higher resolution images than most digital cameras.
- More sensitive films have more visible grain.
- Noise/grain tends to appear more on pictures with long exposure time, but, film grain is not affected by exposure time, but the marginal sensitivity of the film can change with lengthy exposures.
- In the terms of speed, which is sensitivity to light, the film camera is not as advanced as digital cameras. To change the speed, the film in the film camera has to change.
For scanning slides and negatives, 600 DPI is the best resolution, as it provides a balanced image of high quality while keeping the scanning times reasonable.
But, if you are scanning a 35mm slide, your scanner resolution should be at least 4000 DPI. This will give you an 18-megapixel scan, which indicates that it will be a high-resolution picture. When I say scan at 4000 DPI, it means that the scanner will squeeze; multiply the height and the width of the 35mm slides at 4000 DPI, which accounts for 4000 pixels for every inch in the image.
This will get you a pixel dimension of 5200*3400.
You can choose the resolution of a 35mm slide according to the size of the print you want, as you do not want your image to look stretched. It could be lower than 4000 DPI.
In conclusion, even if a film is not used much in the modern era, it is still used by many photographers to capture even the minute details. Films are being digitized or printed through digital scanners and printers. Although, if you want a well-printed photo, you need to set the resolution following your needs. Digital photography and film photography have quite a few differences, especially in the area of resolution, but it depends on the choice of the photographer.