Read
Open a PDF and read it normally in a continuous vertical view.
Highlight what matters.
Recall before you reveal.
Reading Mode turns your own highlights into simple retrieval prompts. The PDF stays on your device, and the app hides only the information you chose to study.
Open Reading Mode →THE FLOW
Five steps. No flashcard setup.
Highlight
Select real PDF text, or mark an exact area on scanned and image-only pages.
Recall
Apply the Red Sheet and the memorization-marker text is concealed, like the physical study workflow. Digital Mask remains an optional alternative.
Reveal
Try to retrieve the answer from memory first, then tap the mask to check yourself.
Learned
Mark a revealed answer as learned. It is skipped next time unless you choose to review learned items too.
THE INSPIRATION
From physical red sheets to a digital recall layer.
Japanese stationery makers such as Kokuyo sell memorization markers that support two related actions: coloring over printed text and writing answers with a second pen, then covering the page with a red sheet so the marked content disappears during review. PixelOrigen borrows that study interaction. Green and blue marks remain readable while the sheet is off; when the digital Red Sheet is applied, PixelOrigen records and conceals those exact regions so the result is reliable on a screen rather than depending on real-world color-filter optics.
Kokuyo also offers an eraser for some memorization-marker ink. PixelOrigen's digital equivalent is a non-destructive Learned state: the highlight stays saved, but mastered answers can be skipped during the next recall session. This is an inspiration claim, not a claim that red color itself improves memory.
See the physical red-sheet example ↗TWO RECALL STYLES
Use the cleaner mask, or the familiar red-sheet view.
Red Sheet combines a red-pass view with stronger digital colour hiding: warm red/orange/pink ink is boosted to blend with red paper, blue/green darken, and black stays black. Your green/blue cover marks become dark covers; saved written answers hide. Tap a marked answer to lift the whole effect locally, then mark it learned. Digital Mask hides only your marked regions and keeps the normal page colours.
The stronger effect goes beyond a physical sheet; it is not a calibrated optical reproduction. Very dark or muted ink, tinted paper and coloured backgrounds can retain contrast. Pictures and logos change too. Older browsers without the required colour-filter support use the basic red-pass view and display a notice. Use an Area mark when an answer must be reliably covered. Learned marks are skipped by default; source colours have no learned state unless you mark their region. Mask is available if the red view is uncomfortable.
WHAT THE RESEARCH ACTUALLY SUPPORTS
The useful mechanism is retrieval practice — not the color red.
Educational psychology research has repeatedly found that trying to retrieve studied information can improve later retention compared with simply restudying it. A 2006 study using educational prose found stronger delayed retention after prior testing than after repeated study. A 2014 meta-analysis also found an overall testing benefit, with effortful recall playing an important role.
Roediger & Karpicke, 2006Test-enhanced learning and delayed retention ↗
Rowland, 2014Meta-analysis of testing versus restudy ↗
Dunlosky et al., 2013Practice testing rated higher utility than highlighting alone ↗
What PixelOrigen does not claim: red light or red color has been proven to boost memory, every learner will improve by the same amount, or Reading Mode guarantees grades or exam performance. Highlighting alone is not the main learning mechanism here; the recall attempt is.
PRIVACY BY DESIGN
Your study document stays local.
The PDF is rendered in your browser. Highlights and reading position are stored locally on the device when browser storage is available. PixelOrigen does not need to upload the PDF to a processing server for Reading Mode.
GOOD TO KNOW
Text PDFs and scanned PDFs both work.
Selectable PDFs can be highlighted from the text layer. Image-only or scanned pages may not contain real text, so Reading Mode also supports a manual area mark for the answer region. OCR is not required for the core workflow. Your learned status is saved with the highlight locally on this device.
READY TO TRY IT?
Open Reading Mode →