CORENTRA GUIDES
Get a better result from your files.
Short, practical steps for common tasks. Review the output before submitting, printing or sharing it.
Combine PDFs in the right order
Use Merge PDF when you need one document containing pages from several PDF files. It combines existing pages; it does not convert them into editable Word paragraphs.
- Open Merge PDF and select at least two PDFs.
- Check the file list. Use the arrows to put each document in the order you need.
- Download the result after processing. Open it and check the first page, last page and the point where each document joins.
For a large collection, combine smaller groups first. If a file is encrypted, unlock it with its correct password before merging. Keep a copy of your originals so you can rebuild a different order later.
Find Merge PDF →Make an image smaller without losing too much detail
File size depends on dimensions, format and compression quality. Reducing a photo’s dimensions often helps more than repeatedly lowering its quality.
- Use Resize Image if the picture is larger than the dimensions you actually need.
- For photos, try JPEG or WebP in Compress Image. Keep PNG when transparency or sharp diagrams matter.
- Compare the file size and zoom into text, faces and fine edges before saving.
JPEG compression is lossy. Repeatedly saving an already compressed JPEG can add artifacts. Work from the original image each time. A PNG may not become smaller, and JPEG replaces transparency with a white background.
Find image tools →Reduce background noise while protecting speech
Noise reduction can also affect quiet syllables, music and overlapping voices. The cleanest-sounding silence is not always the clearest-sounding speech.
- Start with a short recording containing both speech and a noisy pause.
- Choose Gentle strength in AI Background Noise Remover or Basic Noise Reducer.
- Compare the original and processed previews at the same volume. Listen for missing word endings and changes in voice tone.
- Try Balanced only if Gentle leaves too much noise. If speech gets worse, return to a gentler setting or use the original recording.
Gentle mode mixes some original audio back into the result. It intentionally leaves more background sound to reduce the chance of losing speech. RNNoise targets speech; it is not a tool for separating two speakers or extracting vocals from music.
Find noise-reduction tools →