A little guide to useful tools
Understand the result and put it to good use.
Three checks before merging a PDF
Keep a copy of each original. When merging PDFs, the input file order determines the order of pages …
Read guide →Margin and markup use different denominators
If revenue is 100 and cost is 60, profit is 40. Margin divides profit by revenue, giving 40%. Markup…
Read guide →What browser-based file processing means
Selecting a file grants the browser access to that file. Ordinary Murphkitsch image and PDF tools pr…
Read guide →Balancing image quality and file size
JPEG or WebP often suit photographs. PNG may suit text, line art and images requiring transparency. …
Read guide →Reading a DNS lookup result
A records represent IPv4 addresses and AAAA records represent IPv6 addresses. MX records identify ma…
Read guide →Check units before calculating
Equal numbers can describe different quantities when units differ. Confusing centimeters with meters…
Read guide →Choosing resolution for PDF-to-PNG
PDF text and lines can remain sharp when enlarged; a PNG has a fixed pixel grid. Doubling the render…
Read guide →Why a PDF may contain no extractable text
A PDF can mix text, photographs and vector drawings. Visible letters may simply be pixels in a full-…
Read guide →Making Korean PDFs portable
If a recipient lacks a font used in your document, rendering may change. Embedding the font in a PDF…
Read guide →Strings that look like numbers in Excel
Postal codes, order IDs and phone numbers can look numeric without being quantities. Interpreting 00…
Read guide →Why an Excel viewer can show an old formula result
An Excel file may store both a formula and its last calculated result. A viewer without a spreadshee…
Read guide →Scan a QR code again before printing
A QR code needs a clear border around it. Cropping tightly or placing other graphics against the cod…
Read guide →Base32 does not keep text secret
Base32 is an encoding that represents bytes with a defined alphabet. It has no secret key or decrypt…
Read guide →The limits of numeric RGB-to-CMYK conversion
RGB describes combinations of light on a screen; CMYK describes ink channels used for printing. A si…
Read guide →Do not round contrast before checking a threshold
Contrast is calculated from the relative luminance of two colors. Black against white gives 21:1; id…
Read guide →Reading principal and interest in an amortization table
This schedule assumes a fixed nominal annual rate divided by 12 and payments at month end. Each peri…
Read guide →Why cash-flow signs matter for IRR
IRR is the periodic discount rate that makes net present value zero. Paying 1,000 initially and rece…
Read guide →bcrypt’s 72-byte limit and Korean passwords
Character count differs from byte count. ASCII letters usually use one UTF-8 byte; Korean syllables …
Read guide →Adding UTM parameters without losing an existing query
A URL may already contain a query such as ?q=search and a fragment such as #section. Appending anoth…
Read guide →Handling a leftover cent when splitting expenses
A shared expense may not divide evenly by the number of people. Splitting 10.00 among three people a…
Read guide →