Turning photos and scans into a PDF: shooting, resolution and order

Camera or scanning app?

Your phone's regular camera is quick, but pages tend to come out skewed with the desk showing around them. Scanning apps, including the document-scan features built into many notes and photo apps, find the four corners of the page, flatten it, crop away the background and boost contrast so text stands out.

For documents you're submitting, a scanning feature gives the cleanest result. If the app produces a PDF, you can use it as is; if it only saves images, collect them and bundle them into a PDF. If you used the regular camera, following the shooting tips and cropping below still gives a very readable result.

How to take readable document photos

• Background: put white paper on a dark desk. Strong contrast between paper and background makes cropping easy and helps scanning apps find the corners.
• Light: a ceiling light directly above casts your phone's shadow on the page. Shoot where light comes from the side, such as near a window, or shift so your shadow doesn't cover the text. Flash tends to cause glare on glossy paper.
• Angle: hold the phone parallel to the page, directly above it. Shooting at an angle turns the page into a trapezoid with smaller text at the top, which stays awkward to read even after cropping.
• Fill the frame: get close enough that the page nearly fills the screen, with all four corners visible. Shooting from far away and cropping later throws away resolution.
• Orientation: hold the phone upright for portrait documents and sideways for landscape ones. Lining up the long side of the camera sensor with the long side of the paper gives the page the most pixels. Shoot a portrait page in landscape and you get wide strips of background with a small page in the middle.
• Focus: tap the text on screen to focus before shooting, then zoom in right away to check the smallest print isn't blurry. If it's shaky, retaking it on the spot is fastest.

Think of resolution as pixels versus print size

Sharpness ultimately comes down to how many pixels capture one sheet of paper. For printing, this is expressed as pixels per inch (dpi): divide the pixel count by the printed length in inches.

An A4 sheet's long side is about 29.7 cm, roughly 11.7 inches. Capture that side at 3,000 pixels and an A4 print is about 256 dpi; at 1,500 pixels, about 128 dpi. The same 1,500 pixels filling the frame with something small, like a business card, gives a much higher density because the printed size is smaller.

For documents that will only be read on screen, about 1,500 pixels on the long side is enough for normal-sized text. Dense contracts in tiny print, or documents that must be printed like the original, may need more. ToolyStation's Images to PDF reduces the long side to 1,500 pixels to keep files light, so for documents full of small print the PDF your scanning app produced may be the better choice.

Photo formats: HEIC, JPG, PNG

• HEIC: the iPhone's default photo format. It's smaller than JPG at the same quality, but many browsers other than Safari, and some programs, can't open it. For photos you'll use in web tools, switch the iPhone camera format to "Most Compatible" or export as JPG when sharing.
• JPG: the safe choice for photos. It's lossy, so quality drops a little each time it's saved; avoid editing and re-saving the same photo many times.
• PNG: mostly used for screenshots and loses no quality, but saving camera photos as PNG makes them very large. Keeping screenshots as PNG and camera photos as JPG is the usual approach.

Before you bundle them

1. Delete what you don't need: blurry shots and duplicate photos of the same page are easiest to clear out now.
2. Crop and rotate: use your photo app's editor to cut away the background and straighten each page. Images to PDF can't crop or rotate, so finish this step first.
3. Hide sensitive details: black out information the recipient doesn't need, such as part of an ID or account number, with your photo app's markup pen.
4. Number the files: with many photos, rename them with 01, 02 and so on, or at least select them in the order you took them.

Ordering and bundling

When you add photos to Images to PDF, each thumbnail gets a page number in its top-left corner. That number is the final page order, so always skim through once. Drag any photo that's out of place; clicking several selects them so they move together.

For double-sided documents, keep each front followed by its back. If you shot all the fronts and then all the backs, your order is front 1, front 2, front 3, back 1, back 2, back 3, so move each back after its front.

Name the file and click "Download as one PDF" and you're done. If it needs to be combined with other documents, continue in Merge & Arrange PDF.

Example: receipts for an expense claim

Imagine submitting nine receipts from a business trip as one PDF for reimbursement.

1. Lay the receipts out by date and photograph them one at a time on a dark surface. Hold long receipts flat at both ends so they don't curl.
2. Crop each photo to the receipt's edges in your photo app, and hide any card number digits that are printed in full.
3. Select the photos in date order, add them to Images to PDF, and check that the thumbnail numbers follow the dates.
4. Name the file something like "TripExpenses_Receipts_20261007" and save it.

Long, narrow receipts become long, narrow PDF pages. If the finance team prints them, "Fit to page" can make the text small, so photographing a long receipt in two halves is another option.

What about location data in photos?

Phone photos carry extra information such as the date, the device model and, depending on your settings, where the photo was taken (GPS). Sending the photo files themselves can pass that information along.

ToolyStation's Images to PDF redraws each photo inside your browser and places the redrawn image in the PDF, so extra information like the shooting location isn't carried into the PDF. The original photo files are unchanged, though, so when you send photos separately, turn off location in your phone's sharing options.

Photographing bound documents and books

Stapled documents and books curve, so text slants toward the middle and the fold casts a shadow. If you can, remove the staple and shoot one sheet at a time. With a book you can't take apart, press the margins flat with your fingertips, away from the text, and shoot one page at a time rather than a whole spread; it reduces the curve.

If your fingers end up in the shot, crop them out, or leave them if they don't cover any text; it won't affect readability. For important documents, a sheet of clear plastic or glass pressed on top works better than fingers.

Copies of ID cards and bank cards

When you need to send a photo of an ID or bank document, show only what the recipient requires and hide the rest as described above. On top of that, overlaying a line such as "For submission to [organization] only" makes it harder for that copy to be reused elsewhere.

You can add that line with the text option in Batch Watermark. Let it overlap the main details slightly, but lower the opacity enough that the recipient can still read your name and number. Then bundle the watermarked images with Images to PDF.

None of the tools on this site can place the front and back side by side on one A4 page. Images to PDF makes each photo its own page, so the front and back end up on separate pages.

When photos come out yellow or dark

Documents photographed under indoor lighting often show white paper as yellowish or gray. Images to PDF keeps the photo's colors as they are, so fix them before bundling.

A scanning app's "document" or "black and white" filter makes the background white and the text darker. With only a photo app, nudging brightness and contrast up and saturation down already cleans things up a lot. Be careful with stamps or color markings, though: a black-and-white filter can wipe them out.

Checks after you've made the PDF

• Is every page upright? A single sideways page makes the reader rotate their screen.
• Is the smallest print readable? Zoom to 100% and check amounts, dates and numbers.
• Are hidden details really hidden? Zoom in and make sure nothing shows through.
• Does the page count match the number of photos? Check the last page number to make sure none are missing.