A DTF spot channel is a separate grayscale raster plane assigned to a production ink role, most often white. It is not the colour composite and it is not PNG transparency. A reliable handoff defines the plane’s role, name, polarity, dimensions and mapping, then verifies all five in the exact RIP/version before output. A familiar label such as W1 is useful, but never universal proof.
Separate colour, alpha, and production ink planes
One design can carry several different kinds of information that look similar in a thumbnail but have different jobs:
- Colour raster: the RGB or CMYK values used to reproduce the visible artwork.
- Alpha: per-pixel opacity attached to a colour image. Alpha can describe a cut-out edge, soft shadow or distress, and can be used as an input when generating white.
- White plane: a separate single-channel mask intended to map to white ink in the production workflow.
- Varnish plane: an optional separate mask intended to map to a clear/varnish role in a workflow that supports it.
- Channel name and metadata: labels and file structures that help an application identify each plane’s role.
These are not interchangeable. A transparent PNG can carry RGB plus alpha, but it does not contain a named white-ink spot channel. A prepress application or RIP may derive white from alpha. Once derived, the white plane has its own geometry and density controls and should be inspected separately.
Likewise, a grayscale image named “W1” is not necessarily a mapped ink. The receiving application must import it as the intended production separation. If it appears as visible grey in the colour composite, disappears, or maps to another ink slot, the file has not completed the handoff.
The TIFF-versus-PNG guide covers the container decision. This article stays with the planes inside a spot-bearing handoff.
Read the channel’s role before interpreting its preview
A channel label identifies the intended separation. Polarity describes how its stored values represent coverage. Use a file containing known solid-white and transparent regions to connect the displayed channel to the intended print result.
| Information | Role in the current NestSheet workflow | What to inspect |
|---|---|---|
| PNG colour and alpha | Approved artwork and its opacity | Source edge, holes and physical print size |
| CMYK | Colour in the production TIFF | Appearance and interpretation in MainTOP |
| W1 | Separate white backing in the production TIFF | Coverage, final choke and mapping to white ink |
| Sheet dimensions | The intended physical layout | Receiving width, height and scaling |
| Mirrored orientation | Transfer orientation in the exported file | An asymmetric reference in the receiving queue |
In the production TIFF, W1 uses 0 for full white coverage and 255 for empty coverage. The receiving application can display a separation through its own preview convention. Check known sample regions and the queue’s assigned ink role when interpreting what the picture means.
NestSheet derives production white from the uploaded PNG artwork. The operator selects a whole-sheet choke of 0, 1 or 2 px. Canvas views help inspect coverage; the exported W1 is the reference for the final edge and thin-detail result.
What the current NestSheet production file contains
The Production DTF preset writes a TIFF containing CMYK colour and one separate white channel named W1. It has five channels in total, uses 300 dpi and is mirrored for MainTOP. The operator’s selected sheet-wide choke is applied during production white generation.
Keep the approved PNG source, print dimensions and copy count with the exported TIFF. This lets the receiving operator check that the file represents the intended batch before judging its channel coverage.
Inspect the file and the queue as separate steps
First confirm the file specification and its physical dimensions. Then open that exact TIFF in MainTOP and inspect W1, colour, orientation and scaling. Use a known white-only mark, a transparent opening and fine text to make the separation check concrete.
For another proposed receiving workflow, obtain the supplier’s requirements for the complete file structure. A useful approval record names the format, channels, polarity, physical size, orientation and actual queue used for the sample. Keep the resulting file and observation with the record.
Why W, W1, and White are not interchangeable promises
Channel naming is a local interface contract. One workflow may look for W1; another may ask the operator to map a plane named White; another may derive white internally and ignore supplied planes. Vendor product families can also change import behavior across versions or queue presets.
NestSheet’s current production preset fixes the white-channel name as W1 and targets MainTOP. Use the MainTOP guide for that handoff. For another queue, establish the expected input and ink mapping with its supplier before approving a proposed file workflow.
The RIP hub links the MainTOP handoff guide for the current production file and planning guides for CADlink and AcroRIP. Compare each with the exact target manual and queue, and approve a controlled sample before using a new receiving workflow.
This is also why multiplying a white plane is not automatically “more white.” Multiple W planes can be a required file structure or printer mapping in a particular workflow, but only the downstream setup determines how they drive ink. The operator should not infer density from channel count alone.
For a UV workflow, establish clear-ink requirements separately with the printer and transfer-film supplier. NestSheet prepares garment-DTF gang sheets and either a CMYK + W1 TIFF for MainTOP or a transparent PNG for RIPs that build white. The DTF and UV-DTF guide helps identify the relevant process questions.
Verify the RIP handoff before printing
Use a deliberately small proof file with obvious colour, white and no-white regions. Import the exported production file into the exact queue that will print it, then verify:
- Physical dimensions: the RIP reports the intended width and height with no fit-to-media scaling.
- Colour composite: expected colour appears once, without a grey spot mask flattened into it.
- Plane discovery: every intended white/varnish plane is visible separately; no unexpected plane appears.
- Names: the imported labels match the names you intended to emit.
- Ink mapping: each plane is assigned to the correct device ink role rather than merely listed.
- Polarity: intended solid-white areas show coverage and intended empty areas show none.
- Alignment: colour and production planes share the same origin, scale, crop and mirror state.
- Underbase geometry: threshold and choke results look correct at hard edges, thin strokes and intentional fades.
- Output settings: screening, ink limits, passes, resolution and queue controls belong to the locally tested RIP/printer setup.
- Controlled print: inspect film and one pressed sample before releasing an unfamiliar format or mapping to a full run.
The visual technique in reading a RIP’s white-channel preview helps distinguish the colour composite from the underbase. The broader DTF RIP comparison is appropriate when the unresolved choice is the RIP itself.
Record the tested combination: NestSheet preset, W1 mapping, file dimensions, RIP product/version, queue, printer and date. That receipt is stronger than any statement that a format is “universally compatible.”
Sources
- CADlink, Digital Factory Direct-to-Film Edition: https://cadlink.com/product/digital-factory-direct-to-film-edition
- CADlink Help, Queue menu — Output: https://help.cadlink.com/website/digital_factory/en/production/menus/queue_menu_output.htm
Mutable vendor documentation checked July 2026. NestSheet’s channel count, W1 name, polarity and TIFF container were checked against the product on 2 October 2026; target-RIP mapping remains version- and queue-specific.
