Getting a PDF under 200 KB without wrecking it
A form portal has refused your upload and given you a number. There are three settings that matter and they matter in a particular order — pulling them in the wrong order produces a small document nobody can read.
First: the resolution ceiling
This is the setting that does most of the work, and almost nobody reaches for it first. A photograph taken on a modern phone is around 4000 pixels across. Placed inside a 190 mm box on A4, that is 535 dots per inch. No printer in an office uses more than 300. No screen shows more than about 100. Four fifths of that data cannot ever be seen, and it is the bulk of the file.
Setting the ceiling to 150 takes the same photograph down to about 1120 pixels across, which is a seventh of the data before a single compression setting has been touched. For a photographed document, 150 is legible; 200 is comfortable; 300 is what to use when a portal explicitly asks for it.
The ceiling never works upwards. A photograph that only carries 90 dots per inch across the page stays at 90, because inventing pixels makes a bigger file and no better page.
Second: colour
A photograph of a printed page is black ink on white paper, plus whatever tint the room light added. Writing the pages in grey usually removes 40 to 50 per cent of what is left after the ceiling, and removes exactly nothing that a clerk reading the document needs.
The exception is anything where colour is the information: a coloured seal, a highlighter mark, a photograph of a face on an identity page. Leave those in colour and find the kilobytes elsewhere.
Third: the size figure itself
Now type the number. The document is written at the settings you chose, its real size measured, and only the pages that dominate the size are re-encoded, aimed from that measurement. Up to five passes, then it stops — and if it stopped above your figure, it says so and gives the closest size it reached rather than handing you an unreadable file that happens to fit.
That last behaviour is deliberate. A 200 KB document whose text has dissolved into rectangles is not a success; it is a rejected application with an extra step.
When the answer is fewer pages
Somewhere around 25 to 30 KB a page, a photographed document stops surviving further compression. If the figure you have been given divided by the number of pages is below that, no combination of settings will get you there honestly. Two useful moves remain:
- Put two or four photographs on each sheet. Four to a sheet quarters the page count and each photograph needs a quarter of the pixels.
- Split the set into two or three documents. Most portals that ask for 200 KB are asking per file, not per application, and will take three uploads without complaint.
If you want to start from the size field rather than read about it, the builder opens there on the small-file page.
Questions that come with a size limit
The document fits the portal but is still too large to email. What now?
Email limits are usually 20 or 25 MB, so a document that fits a 200 KB portal is not the problem — it is the original photographs going along with it. Send the PDF instead of the pile: one document at 150 DPI in grey is a small fraction of the photographs it was made from. If one PDF is still too heavy, split the pages across two documents and save each with its own size target — or open the 200 KB builder, which starts with every one of those levers already set.
Is 200 KB even possible for a ten-page document?
At 150 DPI and in grey, ten pages of photographed text land somewhere between 300 and 600 KB. Ten pages under 200 KB means about 20 KB a page, which is roughly a fax. If the portal genuinely wants ten pages in 200 KB, it is worth checking whether it wants them as one document at all — many accept several uploads of a few pages each.
Why does the quality setting do so little on its own?
Because JPEG compression only gets to work on the pixels you gave it. A 12-megapixel photograph squeezed hard is still 12 megapixels of squeezed photograph. Remove the pixels first with the resolution ceiling and the quality setting has far less to fight.
Does grey make the text harder to read?
For a photographed document, no — usually the opposite. The colour in that kind of photograph is a cast from the room light rather than information, and removing it leaves the contrast between ink and paper untouched. It is a bad idea only where colour carries meaning: a stamped seal, a coloured highlight, a photograph of a person.