The signature is where people get stuck
A signature should be cheap to compress — thin dark strokes on white paper is about the least demanding thing an encoder can face. When a signature file refuses to shrink, the cause is almost always that the background is not actually white. A photograph taken in dim light produces a grey, grainy field, and that grain is noise, which is expensive.
The fix is lighting rather than settings. Photograph the paper in bright, even daylight so the background reads as genuinely white, and the file size collapses without touching quality.
The photograph
A recent photograph, face on, against a plain light background, cropped so the head and shoulders fill the frame. Many SSC notifications require a photograph taken within a stated recent period, and some require the date to be visible in the image itself — check the notification, because this condition catches people out and is not something a compression tool can fix afterwards.
Read the notification for the numbers
The size limits and pixel dimensions for photograph and signature are published in each examination notification and differ between examinations and between years. Take the figures from the notification for the examination you are applying to.
Questions
- Why will my signature not compress below the limit?
- Because the white paper is not registering as white. Under weak indoor light a camera records a mottled grey field full of sensor noise, and noise is the most expensive content an encoder can be given. Retake it in bright daylight, or raise the exposure so the paper is properly white, and the file size falls dramatically.
- Should the signature be scanned or photographed?
- A scan is more reliable because it is evenly lit by design and produces a genuinely white background. A photograph works well provided the light is bright and even and you shoot from directly above so the paper is not skewed. Either way, crop tightly around the signature itself.
- Can I reuse the photograph from a previous application?
- Only if it still meets the current notification, which often specifies that the photograph must be recent and sometimes that a date must appear in it. Reusing an older photograph is a common cause of rejection at the verification stage rather than at upload, which is much more costly to discover.
- What should I keep after submitting the application?
- Keep the uncompressed photograph and signature, the reduced versions you actually uploaded, and a copy of the confirmation page. Later stages frequently ask for the same images at different dimensions, and starting again from the untouched originals gives a better result than reducing an already reduced file a second time.