How to make a thumb impression for exam forms
Banking forms (IBPS, SBI, RBI, NABARD), NEET, HTET, DSSSB and IAF Agniveervayu ask for a thumb impression upload. Most people have never made one at home. A smudged black blob is the usual result — and smudged impressions get rejected.
Here is how to make a clean one in about five minutes, and how to get it to the exact size your exam wants.
What you need
- A stamp ink pad (black or blue). Any stationery shop has one for about ₹30–50.
- A plain white A4 sheet — printer paper, no lines.
- Tissue or a cloth to wipe your thumb.
- Your phone, and daylight or a bright room light.
No ink pad? A blue or black ballpoint refill rubbed on the thumb works in a pinch, but an ink pad gives a much cleaner print.
Which thumb?
Banking notices ask for the left thumb. If you do not have a left thumb, they allow the right one — the rule is in the notice. NEET is different: it asks for all fingers and thumbs of both hands. DSSSB asks for left and right thumb as two separate files. Read your exam’s rules first.
Step 1: Make the impression
- Wash and fully dry your hands. Oily skin smudges.
- Press your thumb lightly on the ink pad. Dab two or three times — do not soak it.
- Check the thumb: the ridges should be inked, not a wet layer of ink.
- Place the thumb flat on the paper and press down with gentle, firm pressure. Count to two.
- For full coverage, roll the thumb very slightly to each side — just enough to print the edges — without letting it slide. Then lift straight up. Sliding or a big roll is what causes smudges.
- Make 3–4 impressions on the sheet, with space between them. You will pick the best one.
- Let the ink dry for a minute before you take the photo.
A good impression shows clear ridge lines across the whole thumb tip. If it is a solid dark patch, you used too much ink. If it is patchy and pale, use a bit more.
Step 2: Photograph it
- Keep the paper flat on a table near a window.
- Hold the phone directly above, parallel to the paper.
- Turn flash off and make sure no shadow falls on the print.
- Get close enough that the impression fills a good part of the screen, then tap to focus.
- Take two or three shots and pick the sharpest.
You do not need a scanner. A modern phone camera captures ridges well if the light is even.
Step 3: Crop, clean and resize
Open Thumb Impression on SahiSize, or go straight to your exam page.
- Pick the photo — it stays on your phone; nothing is uploaded.
- Crop around one impression, leaving a small white margin. For banking the crop box is square.
- Clean — this makes the paper white and the ink darker, without filling in the ridges.
- Fit to your exam — pixels and KB are set from the preset.
- Check the ticks and download.
Thumb impression sizes for common exams
Always check the latest official notice — these are from recent notices and can change between cycles.
| Exam | Size | KB | Notes |
|---|---|---|---|
| IBPS PO, SBI Clerk, RBI, NABARD | 240 × 240 px (3 × 3 cm at 200 DPI) | 20–50 KB | Left thumb, black or blue ink, white paper |
| NEET UG | KB only | 50–200 KB | All fingers and thumbs, both hands |
| HTET | KB only | 10–50 KB | Thumb impression |
| DSSSB | KB only | up to 40 KB each | Left and right thumb, separate files |
| IAF Agniveervayu | KB only | 50–100 KB | Left thumb |
| SSC GD | Not in the notice | Check the form | Only if the online form asks for it |
A note on NEET: the bulletin mentions two ranges (10–200 KB in one place, 50–300 KB in another). SahiSize uses 50–200 KB, which satisfies both.
The NEET finger impressions
For NEET you need all ten prints. The usual way is:
- On one A4 sheet, make the four fingers of the left hand in a row, then the left thumb next to them.
- Below that, do the same for the right hand.
- Write “Left hand” and “Right hand” above each row in small letters, if the form or bulletin asks for labels.
- Photograph the whole sheet in one shot, flat and sharp.
Check the NEET form for whether it wants one image or separate images per hand, as the layout has changed between years.
Common mistakes
- Too much ink. The ridges fill in and the print becomes a blob. Dab lightly.
- Sliding or over-rolling the thumb. It smears the edges. Press flat, roll only slightly, and lift straight up.
- Lined paper or coloured paper. Use plain white.
- Shadow of the phone on the print. Move the light or the phone.
- Photo of a photo. Never photograph a print shown on another screen.
- Wrong hand. Banking wants the left thumb unless you do not have one.
FAQ
Can I use blue ink?
Yes for banking — the notice says black or blue. NEET also allows black or blue. Black usually comes out a little crisper after compression.
My file is only 12 KB but IBPS wants 20–50 KB. What now?
A clean thumb print on white paper compresses very well. SahiSize’s preset raises quality and, if needed, adds invisible padding so the file reaches 20 KB without changing how it looks.
Can I make the thumb impression with a mobile app or fingerprint sensor?
No. Exams want an ink impression on paper. A phone fingerprint sensor does not produce an image you can upload.
Do I need the same thumb impression at the exam centre?
Biometric thumb or finger scans are often taken at the centre and during document verification. Your uploaded impression should be a genuine one of your own thumb.
Is SahiSize the official tool of any exam?
No. SahiSize is independent and not linked to any exam body. Always check the latest official notice. Next, see the handwritten declaration guide and the signature scanning guide.